Diameter
noun
Fix the diameter. It is the wrong diameter and must be a new diameter. Test it now, what's the diameter?
ちょっけい
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.
直径100フィートもある巨大な新種のクラゲが、ビーチをドロドロにしてしまいました。
A new, giant 100 foot in diameter species of jellyfish oozed on the beach.