Molecula

Part of speech: noun

Definitions

1. A minute particle that makes up a chemical substance and is the smallest unit retaining its chemical properties
2. A fundamental unit consisting of two or more atoms joined together, essential in the study of chemistry
3. The basic building block of matter formed by atoms bonded together, defining the substance's characteristics and reactions

Etymology: "Molecule" comes from Latin "molecula," a diminutive of "moles," meaning "mass" or "barrier." The Latin suffix "-cula" marks something small, so the word literally means "little mass," a tiny portion of a larger heap. That is a striking reversal: the modern sense describes the smallest unit of a substance, yet its root points to bulk rather than fineness. The Latin term was used in the sense of a small mass, and it passed into English as a scientific term, where it came to name the tiniest grouping of atoms that still carries a substance's chemical identity. The shift from a general "little mass" to a precise chemical unit happened as chemists needed a name for particles smaller than a visible sample, and they reached back to Latin, the common language of learned writing, to find one.