Yes, the noun 'octagon' is a countable noun, the plural form is octagons.
Examples:
An umbrella is a common form of an octagon. (singular)
The pattern is a series of octagons in traditional colors. (plural)
Yes, property is a countable noun.
The noun 'octagon' is a concrete noun, a word for a physical thing.
Yes, castle is a countable noun: We have two castles, one castle in the countryside and one castle on the ocean.
noun
Wood is generally considered an uncountable noun when referring to the material as a substance, such as in "The table is made of wood." However, when referring to different types or pieces of wood, such as "three woods," it can be treated as countable. The context determines how it is used in terms of countability.
The noun 'hill' is a countable noun. The plural form is 'hills'.
Shark is a countable noun.
No, "np" is not a countable noun.
Prawn - prawns is the plural - is a countable noun
Transport is both countable and uncountable as a noun.
Yes, property is a countable noun.
The noun 'animal' is a countable noun. The plural form is animals.
Yes, the noun 'marriage' is a countable noun. The plural noun is marriages.
The noun meeting is a countable noun; for example: We have a meeting this afternoon. We've had two meetings already this week.
The noun 'desert' is a countable noun; the plural form is deserts.
The noun analysis is a countable noun; the plural form is analyses.
The noun utensil is a countable noun; one utensil, many utensils.