The masculine noun rechem (the accent is on the first syllable, since it is a segolate noun) means “womb” in Hebrew.
Words that share the root include “compassionate” (rachum), compassion (rachamim), and the verb to show compassion (racham).
The root refers to the deep love found or rooted in some natural bond (such as childbirth). In the Piel it is used for the deep inward feeling we know variously as compassion, pity, mercy.
God shows the one who fears Him this same sort of compassion:
Like as a father pitieth his children, so the LORD pitieth (richam) them that fear him