ACROSS Copy link • ACROSS 1. adv., in transversum; ex or de transverso; per transversum. Something comes across my mind, aliquid mihi de improviso objicitur. Crosswise, Vid: To shake hands across, alicujus manus decussatim constringere. 2. preposition, transitive, To march an army across the Rhone, trajicere exercitum Rhodanum or trans Rhodanum.