balji gismu

x1 is a bulb [body-part] of plant/species x2; [metaphor: rounded, bulgy].

See also punli, batke.


In notes:

batke
x1 is a button/knob/[handle] on/for item x2, with purpose x3, made of material x4.
punli
x1 is a swelling/protrusion/convexity [shape/form] at/in/on x2, of material x3.
selbalji
x2=b1 is a bulb [body-part] of plant/species x1=b2; [metaphor: rounded, bulgy].