Word Request: A word that would describe how seconds (or other unit) relate to minutes (or other unit)

For example, if I had the sentence: A minutes ______ are seconds. What word would work here? It would also fit in the sentences below.

• A byte's _____ are bits.
• A byte is split up by eight ______ called bits.
• Tom asked "what is the ______ for a yard? Billy answered "A yard's ______ is called a foot."

I think you get the idea of the word (or short phrase) that would work here.

• I think you are looking for something like "constituent" or "sub-unit" The problem is that a yard might be defined as 3 feet or 36 inches or 91.44 centimeters. So at best you might say that one of a yard's defining units is the foot Really though the idea is that a minute can be defined in terms of seconds or a yard in terms of feet, but the word you seek implies that they can only be defined that way- which is why it doesn't exist.
– Jim
Dec 25, 2014 at 6:57
• I get what you are saying. So would saying "A constituent of seconds are called milliseconds" work? Dec 25, 2014 at 7:01

Subunit is the word that would work here. According to Collins English Dictionary definition of subunit is "A subdivision of a larger unit" or "a distinct part or component of something larger".

Units.

A byte is split into 8 units, called bits.

The problem with addressing, specifically, only one level down the hierarchy is that it's unclear how far down one level is, especially in the metric system.

A year is broken down into months, yes? But then a month is - weeks? How many? 4.3 or so? It doesn't work perfectly.

A meter goes to centimeters? decimeters? millimeters? It's not consistent.

Anyway, 'unit' is a term that should work for you. 'Child unit' would specify that you want something smaller than the implied 'parent.'

The base unit of time is the second. In the imperial system, the base unit of length is the foot.

Base Unit: (SI base unit -Wiki)

The Système International d’Unités (SI), or International System of Units, defines seven units of measure as a basic set from which all other SI units are derived.