1. To think carefully about something for a long time before reaching a decision: Jeremy has been pondering for weeks about where he should move.
2. To weigh carefully in the mind; to consider thoughtfully: Paula thoroughly pondered her next undertaking about changing her vocation as a teacher to a politician.

Tom ponders everyday about what he can do to improve his physical condition.

To ponder something is to consider it carefully and seriously, to weigh it thoughtfully, and to think long and hard about it.

Marge left her son, Jimmy, alone so he could ponder about his misbehavior.

3. Etymology: from Middle English in the sense of "to appraise, to judge the worth of"; then from French ponderer, "to consider"; from Latin ponderare, "to weigh, to reflect on" which came from pondus, ponder, "weight".