1. Tetrahedron
   Tetahedrin
2. Titrohedran
   Tedrahedron

In 1912, a tetrahedron was described as "a geometric shape that includes no more than four equilateral triangles." It was also "a figure with a polygon base and four equilateral triangular faces," or "one of five ordinary solids." A more modern definition of a tetrahedron is "a solid formed with four plane faces."

1. Beaceus
   Berceuse
2. Berceese
   Bercause

Definitions for "berceuse" included "a song for a crib" and "a softhearted musical composition." The word first appeared in 1876 and is derived from the Old French "bercier," meaning "to rock" a baby in a cradle.

1. Girotarr
   Garroter
2. Gerrater
   Garrotier

"Garroter" means "someone guilty of the offense of garroting." "Garrotte," with an extra letter "t," is a 1620s word that described a "Spanish style of capital punishment by way of strangulation." A 1912 definition of "garrote," with one letter "t," is "to seize someone by the throat, causing the person to be weak in order to easily rob him."

1. Opiscele
   Opuscolle
2. Opuscule
   Opuscuple

A 1912 definition of "opuscule" was "a minuscule work" or "brochure." The term first appeared in 1530 to mean "a minor or petty work," a synonym for "opusculum."

1. Voossoir
   Vaussoir
2. Voussoir
   Vousir

In 1912, a "voussoir" was described as "one of the wedge-shaped stones used to make a bridge's arc." The term was first used in 1728 to mean "a wedge-like element used to construct an arch or a vault."

1. Scioptione
   Scopeticon
2. Sciopticon
   Sciopticin

The 1912 definition for "sciopticon" was "a magic lamp for presenting photographs." The word is rarely used today.

1. Usoorer
   Usurer
2. Usiriar
   Usurerve

The 1912 definition of the word "usurer" hasn't changed. It has been defined as "someone who lends money at steep interest rates."

1. Welwitschia
   Wielweetschia
2. Weelwitischa
   Welwetschia

Today, "welwitschia" means "a desert plant found in southwestern Africa." A 1912 definition is "plant of Africa that produces only two large leaves."

1. Thaumotrope
   Thaumatrope
2. Thraumotrop
   Thamatrope

The "thaumatrope" was a popular optical toy in the 19th century. A formal definition from 1912 is "an optical toy that presents the continuance of an illusion to the eye after a lucent element is removed."

1. Loquacious
   Loquiciaus
2. Laqucious
   Loquatious

"Loquacious" currently means "possessing a tendency to talk a great deal," the same as it did in 1912. The adjective first appeared in the 1660s.

1. Creveen
   Cirvina
2. Cervine
   Cerveen

"Cervine" first appeared around 1828 to mean "similar to a deer." A nuanced definition of "cervine" from 1912 was "of a tawny-brown or taupe color."

1. Equopois
   Equipoise
2. Equipisse
   Equipoese

"Equipoise" first appeared in the 1650s as a contraction of the phrase "equal poise," which is a 1550s expression. A modern definition of "equipoise" is "a counterbalance of strength or principals."

1. Avicalariem
   Avicularium
2. Aviculorim
   Avicularoom

"Avicularium" is a zoology term that means "minor clasping process that mimics a bird's head that's seen on certain bryozoans." A 1912 definition includes the clause: "that continually nips; seen in a substantial number of Polyzoa."

1. Phecind
   Ficond
2. Fecund
   Fecland

The modern definition of "fecund" means "the skill to generate a lot of progeny or outgrowth." In 1912, "fecund" meant "fruitful" or "prolific."

1. Calaboose
   Calabose
2. Calaboise
   Calaboss

"Calaboose" first appeared in 1792 as an American term that means "prison." The word is derived from the Spanish word "calabozo," which means "dungeon."

1. Kimograph
   Kymograph
2. Kymigrah
   Krymograph

In 1912, "kymograph" was defined as "a device used for calculating blood pressure." Today, a "kymograph" is "an apparatus that pictorially records motion and pressure."

1. Igniminius
   Ignominis
2. Ignominious
   Ignomanious

"Ignominious" first appeared in the 15th century to mean "dishonorable" and "distinguished by humiliation." In 1912, the term held similar meanings: "scandalous," "shameful" and "infamous."

1. Mormose
   Marmose
2. Marmis
   Marmoose

The modern term that resembles "marmose" is "marmoset," which is "a little Central or South American primate." A 1912 definition of the now-archaic term "marmose" was "a genus of little opossum."

1. Quietzal
   Queitzal
2. Quetzal
   Quetzale

A 1912 definition of "quetzal" is "bird of paradise from America." Today's definitions are more elucidating. A "quetzal" is "a trogon family bird as seen in the American tropical forests." "Quetzal" is also defined as "a basic unit of Guatemalan money."

1. Timpinum
   Tympanum
2. Tymponum
   Timpanum

"Tympanum" is most commonly associated with "eardrum." Definitions include: "membrane wall that divides the internal ear from the external ear," "an empty wheel with the shape of a drum," and "the leveled triangle-shaped subdivision of a pediment."

1. Ridotio
   Redetto
2. Ridotto
   Ridot

Today, a "ridotto" describes "a public masquerade gathering of the 18th century that consisted of music and dance." Definitions from 1912 include "dance and music community entertainment that originated in Italy" and "public gathering."

1. Ypinoomeutida
   Yponomeutidae
2. Eyponimetidae
   Eponomenutide

"Yponomeutidae" is considered a new Latin term that means "species of tineoid moths." A 1912 definition of "yponomeutidae" is "ermine moths."

1. Auriferous
   Awifirous
2. Auriferius
   Aurtherous

"Auriferous" first appeared in 1727 to mean "that which contains gold." Definitions from 1912 include "possessing gold" and "yielding or bearing gold."

1. Pernickety
   Pernickity
2. Purnickaty
   Pirsnickety

"Pernickety" is a British term that means "fussy" or "overly-emphasizing trivial matters." Expressive 1912 definitions include "trim," "overly particular" and "overnice."

1. Zigimorphous
   Zygamorfous
2. Zygomorphous
   Zygomorfous

"Zygomorphous" is a botany term that means "a flower that possesses just one symmetry plane; or one that is symmetrical bilaterally." A 1912 definition is "something which is formed as a yoke; pertaining specifically to subdivided flowers."

1. Sasurrus
   Susurrus
2. Susurros
   Susurris

"Murmuring," "rustling" and "whispering" are modern synonyms of "susurrus." In 1912, "susurrus" held the meaning, "a delicate whisper as that of a light breeze; the far-off sound of bees humming."

1. Deaconal
   Diaconal
2. Daconial
   Diacinal

In 1912, "diaconal" meant "relating to a deacon." Today's meaning of "diaconal" also attributes the term to the female form "deaconess."

1. Hacnoid
   Hackneyid
2. Hackneyed
   Hackeyed

"Hackneyed" is an adjective that means "void of ingenuity." "Worn down" and "commonplace" are 1912 definitions of the term.

1. Nubbon
   Nubbin
2. Nubbian
   Nabbin

"Nubbin" means "remnant" or "small bit," as in "nub." It also means "that which is underdeveloped when equated with others of its type." In 1912, "nubbin" meant "little or flawed ear of maize."

1. Summambalism
   Samnambulisn
2. Somnambulism
   Somnanbilism

"Somnambulism" has preserved its meaning since 1912; it means "the act or exercise of sleepwalking." The term is of French origin and first appeared in 1786 to mean "traveling in one's sleep, or hypnotized."

1. Portmonaie
   Partimonnoie
2. Portemonnaie
   Pertemonnaie

In 1912, "portemonnaie" was written without the hyphen that is used in the word today. This French word means "a purse or little pocketbook."

1. Riaficimanto
   Rifacimento
2. Rifacimentio
   Rifacimanto

In 1912, "rifacimento" meant "the adaptation or remake of a book or play." The Italian word has preserved its meaning since then. The plural form is "rifacimenti."

1. Xenion
   Zeenan
2. Xenon
   Xinen

A 1912 definition of "xenon" was "the weightiest of the five newly discovered fundamental substances of a gas form in the atmosphere." Today's definition for "xenon" is "chemistry element with atomic number 54; a noble gas within its series; acquired through purification of liquid air."

1. Vepirous
   Viperous
2. Viparious
   Vipirious

"Viperous" is an adjective synonymous with "cancerous" and "viperine," and means "having the characteristics of a viper." The 1912 definitions of this term are the same.

1. Juveescint
   Juveenescet
2. Juvenescent
   Juveniscant

In 1912, "juvenescent" meant "turning young." Modern definitions of the term include "youthful" or "youthful change."