Another word for enrolls could be sign- up or matriculation, or enlist.
Constellation or zodiac sign
character, sign
yes
Call sign?
up and down
I have listed this as part of another answer here: What_is_sign_for_king_in_asl
Placard , notice , poster or sign .
sympton
Mercedes logo, maybe
sign, prediction, warning, prenotion
Synonyms for sign up include enlist, enroll, recruit.