Learn English – “pseudo-“, “quasi-” “semi-” and

meaningprefixes

I was wondering about the meaning of "pseudo-", "quasi-" "semi-" and possibly other related prefixes, in general cases.

Particularly, in engineering and science, there are quite a few terms named with these prefixes. For example, "quasi-integrable", "pseudo-Newton method", "semigroup". But I never get to understand their differences in usage.

Best Answer

Pseudo- comes from the Greek for false/lie and refers particularly to something not genuine.

Quasi- comes from the Latin for almost and refers to something that is almost something else.

Semi- is the Latin for half and refers to something that is half-something else

In late usage, however, all three have been used to mean sort-of-