一事 is read as いちじ (ichiji) and means one thing.
いちじ
ichiji
いちだいじ
important matter
しごとだいいちしゅぎ
workaholism
だいいちじしゃんはいじへん
Shanghai Incident (1932)
ひとこと
single word
いっか
(one's own) style
いちや
one night
いちど
temporarily
いっぽう
on the one hand
いったい
one Buddhist image (or carving, etc.)
いちいん
one person
いっさい
absolutely (not)
ひとくち
one share