起首 is read as きしゅ (kishu) and means start.
きしゅ
kishu
おきあがりこぼし
tumbler
きてん
starting point
きしかいせい
revival from the brink of death
きいん
cause
きそう
drafting (e.g. a bill)
きどうそう
ingressive aspect
きどうがめん
startup screen
きりつせい
orthostatic
きどうき
starter
きどうがわ
initiator
きじゅうき
crane
きしてん
origin (of an artery, nerve, etc.)