How to Use Thesis Plural (Explained, With Examples)

What’s the plural of “thesis”?

A thesis is “a long piece of writing on a particular subject, especially one that is done for a higher college or university degree.” The plural of thesis is theses (pronounced thee-seez).

👍🏼Usage Note

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She submitted her thesis on quantum mechanics.

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The professor supervised several theses this year.

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He wrote two thesis during his studies.

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The students presented their thesises at the conference.

Thesis is singular.
The plural of thesis is theses (thee-seez).

Nouns that end in –sis

Many Greek-origin nouns ending in -sis form their plural by replacing -is with -es. Examples include analysis → analyses, crisis → crises, oasis → oases, synopsis → synopses, and thesis → theses.

singular	plural
thesis	theses
analysis	analyses
crisis	crises
oasis	oases
synopsis	synopses

Greek nouns in English

💡Study Tip

For the plural of “thesis,” change the -is ending to -es: theses.

Examples of “thesis” and “theses” in sentences

Sentences with “thesis” (singular)	Sentences with “theses” (plural)
She is writing her thesis on climate change. His thesis was well received by the committee. The thesis must be submitted by the end of the semester.	The university library stores all graduate theses. Several theses on linguistics were presented. The professor has supervised many theses over the years.

Word	Similar words
thesis	dissertation, paper, treatise, essay, argument, proposition

Origin of the word thesis

Thesis comes from Greek θέσις (thésis), meaning “a proposition, a setting down, position, thesis,” from the root τίθημι (títhēmi), “I put, place, set.”