Sunflower seed, botanically

• Hard, dry one-seeded fruit
• Part of a strawberry
• Fruit of the buttercup
• Outer part of a strawberry
• Part of a buttercup

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Achene \A*chene"\, Achenium \A*che"ni*um\n. [Gr. 'a priv. + ? to gape.] (Bot.) A small, dry, indehiscent fruit, containing a single seed, as in the buttercup; -- called a naked seed by the earlier botanists. [Written also akene and ach[ae]nium .]

Wiktionary Word definitions in Wiktionary
n. (context botany English) A small, dry, indehiscent fruit, containing a single seed, as in the buttercup.

WordNet Word definitions in WordNet
n. small dry indehiscent fruit with the seed distinct from the fruit wall

Wikipedia Word definitions in Wikipedia
An achene (Greek ἀ, a , privative + χαίνειν, chainein , to gape; also sometimes referred to as akene and occasionally achenium or achenocarp ) is a type of simple dry fruit produced by many species of flowering plants . Achenes are monocarpellate (formed ...