this are irregular nouns
Those words are called irregular nouns.
The term for words that are the same in both singular and plural forms is "unchanged plural." Examples include "sheep," "deer," and "fish."
Some nouns that have the same form for singular and plural are:one deer, two deeraircraftsalmontroutsheepswineoffspringpoliceAnother group of nouns are the binary nouns, words that are a shortened form for 'a pair of', for example:one pair of glasses, two pairs of glassesbinocularspantsjeansshortsscissorstweezerstongs
"Hypotheses" is the plural form of the word "hypothesis."
No. The term analysis (examination, study) is singular. The plural is analyses.(* In British English, the third person singular present tense is also spelled analyses, whereas in US English, the verb is analyzes.)
The term "gulf" is singular. It refers to a large area of sea or ocean that is partly enclosed by land. If referring to multiple gulfs, it is correct to use the plural form "gulfs."
Trousers, pants, overalls, minutes (as the record of a discussion), agenda (technically this has a singular form, "agendum", but I haven't heard or seen that in decades.) There are also many collective nouns that are usually considered singular in grammar and meaning in the United States but often treated as plurals in England: government, company, firm, etc. The term "United States" itself was often treated as plural before the Civil War but is now almost universally treated as singular.
plural-singular nouns
"Hypotheses" is the plural form of the word "hypothesis."
Criterion is the singular. The plural is criteria.
The medical term "dysphagia" (trouble swallowing) is a noun, but it is not singular or plural.
Yes there is. Believe it or not, the plural of moose is simply moose.Moose is one of the words in English that the singular and the plural are the same word.Example sentences:A moose was standing near the edge of the trees. (singular)Two moose were standing near the edge of the trees. (plural)Contrary to popular belief, Meese, Moosen, and Mooses simply aren't words.
Mitochondria is already plural. The singular form is Mitochondrion.Mitochondria IS plural. The single form is mitochondrion.
the singular term is TRIVIUM. Trivia is already in plural form
phalanges
The noun simplicity is the singular form; the plural form is simplicities.
The word "trachea", the term used for the wind-pipe, is in the singular. The plural is "tracheas" or, infrequently, "tracheae", both of which are recognized by the dictionary.
Organisms is the plural of organism
Economics is a collective term. It is used in the singular.