octad

the cardinal number that is the sum of seven and one ;

octadecanoic acid

a waxy saturated fatty acid; occurs widely as a glyceride in animal and vegetable fats ;

octagon

an eight-sided polygon ;

octahedron

any polyhedron having eight plane faces ;

octal digit

a digit from 0 to 7 in octal notation ;

octal notation

any mathematical notation that uses 8 different characters (usually the digits 0 to 7) ;

octal number system

a positional system of numeration that uses octal digits and a radix of eight ;

octal numeration system

a positional system of numeration that uses octal digits and a radix of eight ;

octameter

a verse line having eight metrical feet ;

octane

any isomeric saturated hydrocarbon found in petroleum and used as a fuel and solvent ;

octane number

a measure of the antiknock properties of gasoline ;

octane rating

a measure of the antiknock properties of gasoline ;

octanedioic acid

a dicarboxylic acid found in cork ;

octans

the constellation that includes the southern celestial pole ;

octant

a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration ;

octave

a rhythmic group of eight lines of verse ; a musical interval of eight tones ; a feast day and the seven days following it ;

octavian

Roman statesman who established the Roman Empire and became emperor in 27 BC; defeated Mark Antony and Cleopatra in 31 BC at Actium (63 BC - AD 14) ;

octavo

the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves ;

octet

a musical composition written for eight performers ; eight people considered as a unit ; a set of eight similar things considered as a unit ; eight performers or singers who perform together ; the cardinal number that is the sum of seven and one ;

octette

a musical composition written for eight performers ; eight people considered as a unit ; a set of eight similar things considered as a unit ; eight performers or singers who perform together ;

octillion

the number that is represented as a one followed by 27 zeros ;

october

the month following September and preceding November ;

october 12

a legal holiday commemorating the discovery of America by Christopher Columbus ;

october 24

a day for celebrating the founding of the United Nations ;

october revolution

the coup d'etat by the Bolsheviks under Lenin in November 1917 that led to a period of civil war which ended in victory for the Bolsheviks in 1922 ;

octoberfest

a strong lager made originally in Germany for the Oktoberfest celebration; sweet and copper-colored ;

octogenarian

someone whose age is in the eighties ;

octonary

the cardinal number that is the sum of seven and one ;

octopod

a cephalopod with eight arms but lacking an internal shell ;

octopoda

octopuses and paper nautilus ;

octopodidae

a family of Octopoda ;

octopus

bottom-living cephalopod having a soft oval body with eight long tentacles ; tentacles of octopus prepared as food ;

octoroon

an offspring of a Quadroon and a White parent; a person who is one-eighth Black ;

octosyllable

a verse line having eight syllables or a poem of octosyllabic lines ;

octroi

a tax on various goods brought into a town ;

ocular

combination of lenses at the viewing end of optical instruments ;

ocular muscle

one of the small muscles of the eye that serve to rotate the eyeball ;

oculism

the craft of an oculist ;

oculist

a medical doctor specializing in the treatment of diseases of the eye ; a person skilled in testing for defects of vision in order to prescribe corrective glasses ;

oculomotor

supplies extrinsic muscles of the eye ;