A*breast" (#), adv. [Pref. a- + breast.]
1.
Side by side, with breasts in a line; as, "Two men could hardly walk abreast."
Macaulay.
2. Naut.
Side by side; also, opposite; over against; on a line with the vessel's beam; -- with of.
3.
Up to a certain level or line; equally advanced; as, to keep abreast of [or with] the present state of science.
4.
At the same time; simultaneously.
[Obs.]
Abreast therewith began a convocation.
Fuller.
© Webster 1913.