Ultramicrometers

Part of speech: noun

Definitions

1. A unit of measurement equivalent to one millionth of a millimeter, often used in scientific contexts
2. Referring to an extremely small scale that is useful in precision measurements
3. Characterizing a metric used in specialized fields to denote minuscule dimensions on the microscale

Etymology: Ultramicrometer is a compound built in English from two existing parts: "ultra-", from Latin "ultra" meaning "beyond", and "micrometer", an instrument for measuring very small distances. The latter is itself a modern formation, combining "micro-", from Greek "mīkros" meaning "small", with "meter", which goes back through Middle English "metere" and Old English "-ere" to the Latin "-arius" suffix, denoting a measuring instrument or agent. Putting "ultra-" in front of "micrometer" yields a word for measures smaller still than those a micrometer can handle. The word's sense rests on the Greek "mīkros" and the Latin "ultra" each doing their job: one marks smallness, the other marks going past a limit. Because "ultra-" is a productive prefix in English, the term is less a fixed item of vocabulary than a label coined on demand whenever a scale of measurement lies beyond the usual instruments.