°A
pro-form; a non-personal pronominal, proadjectival, or proadverbal form, in Esperanto regularly formed, indicating which?, that, some, none, and every, as applied to people, things, type, place, manner, reason, time, or quantity, as:
kiu ‘who’ (which person?),
iu ‘someone’ (some person),
tie ‘there’ (that place),
ĉie ‘everywhere’ (all places), etc.