idea
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
Medium is already singular. The plural is mediums.
Phenomenon is the singular form of phenomena.
The singular form of "rays" is "ray".
The word 'Phenomenon' is singular. The plural form is 'Phenomena'.
Idea is Singular, Ideas is plural.
The word ideas is plural. The singular is idea.
ideas ideasIdeas is already plural. The singular is idea.
"idee" is the Italian word for "ideas" but in the singular, the Italian word is the same as the English one. I mean English - Italian = idea - idea :) get it?
ideas I think the querent meant a singular word. "Guess" could work.
"To Think" is a verb. Verbs cannot be singular or plural as you can't have a number of "thinks." You can think many thoughts or just one thought, but thinking is strictly an action word.
Plethora is singular and the plural form is plethoras
It looks like you are trying to spell the word ideas. The singular form is spelled as idea.
Yes! The word 'contradiction' is a noun, a singular, common, abstract noun; a word for ideas, elements, or features that are in opposition; a word for someone or something with conflicting ideas, elements, or features; a word for a concept; a word for a thing.
The noun 'theory' is a singular, common, abstract noun; a word for a supposition or a system of ideas intended to explain something; a word for a concept.
Singular and divine, or simply put, One God.
"Has" is singular, e.g. He has, she has. "Have" is plural, e.g. They have, we have. The exception is "I" - e.g. I have.