The plural of iron is "irons."
The plural of compass is compasses.
"Force" is singular and "forces" is plural.
The plural for motion is motions.
Pelvimeters is the plural of pelvimeter
The plural of thermometer is thermometers.
It depends on the usage. This metal is heavy. its a noun. Iron is a type of metal. is an adjective because its describing the iron.
There is no specific collective noun for steam engines, in which case any noun suitable for the context will work; for example a collection of steam engines, a display of steam engines, a museum of steam engines, etc.
The plural of "she" is "they", so the plural of "she had" is "they had".
The plural of 'this' is 'these' and the plural of 'that' is 'those'.
Isthmi is plural. There are actually two plural forms. I will list them from singular to plural. Isthmus - Singular Isthmi - Plural Isthmuses - Plural
The plural of rose is roses. The plural possessive is roses'.
The plural form of can is cans.
Knights is a plural. It is the plural for knight.
applied is does not have a plural but is apply it does have a plural.
The plural is a regular plural, attics.
The plural of 'bunch' is bunches.The plural of 'ant' is ants.The plural of 'batch' is batches.The plural of 'day' is days.The plural of 'chimney' is chimneys.The plural of 'tomato' is tomatoes.The plural of 'umbrella' is umbrellas.The plural of 'donkey' is donkeys.The plural of 'sky' is skies.The plural of 'foot' is feet.The plural of 'show' is shows.
The plural for the noun loss is losses; the plural possessive is losses'.