noun
first thing in the morning
Colloquial noun/adverb meaning the very first activity or time slot of the morning, often used in business or daily planning contexts.
朝イチでメールをチェックする。
I check my email first thing in the morning.
明日の朝イチに会議が入っている。
I have a meeting first thing tomorrow morning.
More standard and slightly formal; 朝イチ is a colloquial abbreviation.
Colloquial abbreviation of 朝一番 (あさいちばん), literally 'morning's first'.