abbreviation of 'where did' (past) or 'where do' (present/future) as a prefix to a question, arisen from slang or quickness of speech. Similar words are who'd, when'd, why'd, how'd, etc, with the relevant meanings.

n. The birth name of somebody who has changed their name. Most commonly attributed to trans people, but can be attributed to any person who has changed their name. (sometimes written as two words: dead name)

v. 1. To call somebody by their deadname.
v. 2. To out somebody's deadname to the public.

1. contraction of where did:

2. contraction of where would: