Let me expound yet another phrase I use regularly.

to wit (to wit): / to WIT /
idiom; adverb

(1) that is to say (idiomatic)
(2) namely (adverbial)

[From the archaic verb ‘to wit’ meaning “to know or be aware of,” from the Middle English verb ‘to witen’ from the Old English verb ‘to witan’ meaning “to know.” General usage of the phrase is adverbial in nature and assumed to be synonymous between “namely” and “that is to say.”]

Usage: I told her there was one major reason she should not go, to wit, it would be too dangerous.