Omission, Abbreviate, Leave Out
noun, する verb
Conserve those letters with abbreviation and it's... an abbreviation! By using omission you were able to abbreviate that word into a smaller word.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
I have to omit the details for now due to time constraints, but I’ll explain it to you later.