cup-shaped structure of hardened bracts at the base of an acorn

squash plant bearing small acorn-shaped fruits having yellow flesh and dark green or yellow rind with longitudinal ridges

squash plant bearing small acorn-shaped fruits having yellow flesh and dark green or yellow rind with longitudinal ridges

squash plant bearing small acorn-shaped fruits having yellow flesh and dark green or yellow rind with longitudinal ridges

a small vacuum tube; used at high frequencies

a small vacuum tube; used at high frequencies

a small vacuum tube; used at high frequencies

a small vacuum tube; used at high frequencies

a small vacuum tube; used at high frequencies

a small vacuum tube; used at high frequencies