Strong's #2910: tuwchah (pronounced too-khaw')

from 2909 (or 2902) in the sense of overlaying; (in the plural only) the kidneys (as being covered); hence (figuratively) the inmost thought:--inward parts.

Brown-Driver-Briggs Hebrew Lexicon:

ṭûchâh

1) inner regions, hidden recesses, inward parts

Part of Speech: noun feminine plural

Relation: from H2909 (or H2902) in the sense of overlaying

Usage:

This word is used 2 times:

 

Job 38:36: "Who hath put wisdom in the inward parts? or who hath given understanding"
Psalms 51:6: "Behold, thou desirest truth in the inward parts: and in the hidden part thou shalt make me to know wisdom."