under consideration; under review; pending
Used when a matter is being examined or discussed and a decision has not yet been reached. Common in business, administrative, and formal contexts.
The proposal is currently under consideration.
The schedule is still under review and is expected to be decided next week.
未定 simply means 'undecided', while 検討中 implies active examination is underway.
Compound of 検討 (kentō, 'examination, consideration') + 中 (chū, 'in the process of').