agaru
上がる

v : lit. "ascend" - 1. To quit being a fan of a band or a certain member 2. To quit the music scene completely and return to normal life

amaban
アマ盤

n : lit. "amateur band" - Another term for a minor indies band

anchi
アンチ

n : lit. "anti" - An anti-fan i.e. a person who outwardly hates a certain band or band member

ankeeto
アンケート

n : Fr. enquette - A survey. These will usually be handed out in the beginning of an event with a packet of flyers. Fill it out after the concert or bring it home and mail it to the band afterwards. Bands use these surveys as a way to figure out what songs are popular in a certain area in order to know they should play them more often, and they are also used to ask what kinds of merchandise fans are interested in

ankooru
アンコール

n : lit. "encore" - When a band will go offstage for a short rest after the main set, while the audience usually chants for an encore. An encore is typically one or two songs, and there can be multiple encores
also written: EN, 餡子 (anko)

aori
煽り

n : lit. "agitations" - Words and phrases a band member (esp. vocalist) says in order to get the audience fired up and moving around e.g. "kakattekoi!" ["come and get it!"]