1. (adv.) Side by side; also, up to date; as, keeping abreast of current events.

2. (adv.) Side by side; also, opposite; over against; on a line with the vessel's beam; -- with of.

3. (adv.) Up to a certain level or line; equally advanced; as, to keep abreast of [or with] the present state of science.

4. (adv.) At the same time; simultaneously.