From an unused root meaning to cut down (trees); the trunk or stump of a tree (as felled or as planted) -- stem, stock.
H1503. geza
[גֶּ֫זַע] noun masculineJob 14:8 stock, stem (Late Hebrew id., compare Syriac stem, trunk) — construct גֶּזַע Isaiah 11:1; suffix גִּזְעוֺ Job 14:8, גִּזְעָם Isaiah 40:24; — stock, stem of a tree Job 14:8 ("" שֹׁרֶשׁ); figurative ׳ג ישׁי 'stem of Jesse Isaiah 11:1 ("" שֹׁרֶשׁ); ג בָּאָרֶץ ׳שֹׁרֵשׁ 40:24 ("" זרע נטע,).