Addition, Growth
Noun and する verb
ぞうか
お正月に餅を食べ過ぎて、体重が五十キロも増加した。
I ate way too much mochi on New Years and my weight increased by 50 kilos.
An increase will add to what you had before. This is an increase, addition, or growth.
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.