tickler

noun

1. a person or thing that tickles.
2. tickler file.
3. Accounting. a single-entry account arranged according to the due dates of obligations.
4. Electronics, Radio. tickler coil.

noun

1. informal, mainly British a difficult or delicate problem
2. Also called: tickler file US a memorandum book or file
3. accounting, US a single-entry business journal
4. a person or thing that tickles