- definite form
- definite integral
- definite kernel
- definite linear form
- definitely divergent sequence
- Mylon, C.
- myriad
- myriagon
- mystic pentagram
- m×n matrix
- ménage number
- ménage problem
- Méray, H.C.R.
- Méré, A.G.C.de
- Müller, D.E.
- Müller, J.G.
- Mülliken symbol
- Müntz, C.H.
- Müntz space
- Müntz theorem
- M⍥bius, A.F.
- M⍥bius band (= Moebius band)
- M⍥bius function
- M⍥bius geometry
- M⍥bius group