The list of com­mon mis­con­cep­tions includes this clarification:

The word “the­ory” in “the the­ory of evo­lu­tion” does not imply doubt in main­stream sci­ence about the valid­ity of this the­ory; the words “the­ory” and “hypoth­e­sis” are not the same in a sci­en­tific con­text (see Evo­lu­tion as the­ory and fact). A sci­en­tific the­ory is a set of prin­ci­ples which, via log­i­cal deduc­tion, explains the obser­va­tions in nature. The same log­i­cal deduc­tions can be made to pre­dict obser­va­tions before they are made. The the­ory describ­ing how evo­lu­tion occurs is a “the­ory” in the same sense as the the­ory of grav­ity or the the­ory of rel­a­tiv­ity.