The tag alias #47400 lycra -> spandex has been approved.
Reason: They're the same thing. Lycra is a trademark for one brand of spandex fabric.
https://e621.net/posts?tags=spandex currently has about 1200 1600 1700+ hits.
https://e621.net/posts?tags=lycra currently has 37 36 37 hits.
Thanks!
edit: update counts as of 2022-02-03
edit: update counts as of 2022-07-04
EDIT: The tag alias lycra -> spandex (forum #298221) has been approved by @bitWolfy.
Updated by auto moderator