Units of Measurement are used to talk about quantity. Common units include:

length: meter, mile, kilometer…
weight: pound, stone, kilogram…
liquid: liter, gallon…

Singular & Plural
Units of measurement usually have a singular and plural form:
I’ve lived here 1 year.
That wall is 3 meters tall.
This tank will hold just 2 liters.
However, if we use the unit of measurement…