D defs.my
Entry 4 senses Webster, 1913

Abreast

/əb-rĕst'/ · A·breast · IPA /əˈbɹɛst/
01 adv. Side by side, with breasts in a line; as, “Two men could hardly walk abreast.”
  1. 1.
    Side by side, with breasts in a line; as, “Two men could hardly walk abreast.”
  2. 2.
    Side by side; also, opposite; over against; on a line with the vessel's beam; -- with of.(Naut.)
  3. 3.
    Up to a certain level or line; equally advanced; as, to keep abreast of [or with] the present state of science.
  4. 4.
    At the same time; simultaneously.[Obs.]
    Abreast therewith began a convocation.” Fuller.