We adore the cross (as, of course, an image of Christ himself) with the adoration of latria

Blackfriars, Oxford

"there is a twofold movement of the mind towards an image:  one indeed towards the image itself as a certain thing, another, towards the image in so far as it is the image of something else.  And . . . the latter movement, which is towards the image as an image [(in imaginem inquantum est imago)], is one and the same as that which is towards the thing [(in rem)]. . . . Consequently the same reverence should be shown to Christ's image as to Christ himself.  Since, therefore, Christ is adored with the adoration of latria [(adoretur adoratione latriae)], it follows that His image should be adored with the adoration of latria [(sit adoratione latriae adoranda)]. . . . no corporeal image could be put for the true God Himself, since He is incorporeal. . . . But because in the New Testament God was made man, He can be adored in His corporeal image [(in sua imagine corporali adorari)]."
And so, even "if we speak of the effigy of Christ's cross [(effigie crucis Christi)] in any other material whatever [rather than of the very cross on which Christ was crucified (ipsa cruce in qua Christus crucifixus est)]—for instance, [of the effigy of Christ's cross] in stone or wood, silver or gold—thus we venerate [(veneramur)] the cross merely [(tantum)] as Christ's image, which [image] we [venerate] with the adoration of latria [(veneramur adoratione latriae)], as stated above."

     Thomas Aquinas, Summa theologiae III.25.3.Resp. and ad 1, and III.25.4.Resp., trans. FEDP, i.e. Shapcote.  Latin from Corpus Thomisticum.  Note that there is no difference in meaning here between adoro and veneror.  The sole distinction is that between movement "towards the image itself as a certain thing", and movement "towards the image in so far as it is the image of [Christ himself]".