द्वितीया =
द्वि + तीय + टाप्
rolling wave + float below connect + basket of rope
meaning: rolling wave below join and float coracle . This is literal meaning of द्वितीया.
Second came to mean द्वितीया because this is second step, at least while teaching, about boating.
This came to mean “objective or “object” of action because after focus on what is to be done, focus is no the receiver of action in second step.