equo ne credite, Teucri! Quidquid id est, timeo Danaos et dona ferentes.
Do not trust the horse, Trojans! Whatever it is, I fear the Danaans even if they are bearing gifts.
Vergil, Aeneis II, 48 and 110-113 and 150 (edited and translated by H. Rushton Fairclough, Virgil with an English translation I, 1916)
saepe illos aspera ponti | interclusit hiems et terruit Auster euntis; | praecipue, cum iam hic trabibus contextus acernis | staret equus, toto sonuerunt aethere nimbi.
Often a fierce tempest of the deep cut them off and the gale scared them from going. Above all, when yonder horse now stood framed of maple-beams, storm clouds sounded throughout the sky.
quo molem hanc immanis equi statuere?
To what end have they set up this huge mass of a horse?
“equus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
“equus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
"equus", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
equus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
Carl Meißner, Henry William Auden (1894) Latin Phrase-Book, London:Macmillan and Co.
to begin a journey (on foot, on horseback, by land): iter ingredi (pedibus, equo, terra)
to ride: equo vehi
to saddle a horse: sternere equum
to mount: conscendere equum
to mount: ascendere in equum
to dismount: descendere ex equo
to be on horseback: in equo sedere; equo insidēre
to sit a horse well; to have a good seat: (in) equo haerere
to put spurs to a horse: calcaria subdere equo
to put spurs to a horse: calcaribus equum concitare
at full gallop: equo citato or admisso
ride against any one at full speed; charge a person: equum in aliquem concitare
to give a horse the reins: admittere, permittere equum
to give a horse the reins: frenosdare equo
to make a horse prance: agitare equum
to manage a horse: moderari equum
the horses are panic-stricken, run away: equi consternantur
to bring horses to the halt when at full gallop: equos incitatos sustinere
to keep horses, dogs: alere equos, canes
to serve in the cavalry, infantry: equo, pedibus merere (Liv. 27. 11)