data file vs tickler

data file and tickler both are nouns.

Word	Noun	Adjective	Verb	Adverb
data file	Yes	No	No	No
tickler	Yes	No	No	No

As nouns, tickler is a hyponym of data file; that is, tickler is a word with a more specific, narrower meaning than data file:

data file: a set of related records (either written or electronic) kept together
tickler: a file of memoranda or notices that remind of things to be done

Other hyponyms of data file include computer file, mug book, mug file, tickler file, editorial file.

data file (noun)	tickler (noun)
a set of related records (either written or electronic) kept together	a file of memoranda or notices that remind of things to be done