different mother; half- (sibling)
Used in compounds like 異母兄弟 (half-brother with a different mother) or 異母姉妹 (half-sister with a different mother). Contrasts with 同母 (same mother).
See also: 同母
He has two half-brothers (from a different mother).
I don't see my half-sister (from a different mother) very often.
younger half-sister (different mother)
half-sibling (different mother)
Compound of 異 (i, 'different') and 母 (bo, 'mother'). The reading いぼ is the on'yomi of both characters.