The subject relation indicates the relationship between the subject and the action of the verb. In New Testament Greek, there are three subject relations: activum or active, passivum or passive, medium or medial. The active relation, corresponding to our corporate form, implies that the subject performs the action of the verb (I loosen), the passive, corresponding to our suffering form, that the subject undergoes the action (I am loosened), and the medial that the subject's own sphere or interest is involved in the action (I loosen in my own interest, I loosen, I let myself be loosened, or in certain cases also: I am loosened). The forms of the passive and the medium coincide for a considerable part, namely in the durative and in the static aspect. In that case, only the designation (med) is used.

In the following Bible verses, the words are italicized that are translations of verb forms whose subject relationship is active, medial and passive, respectively:
Matt.3:11  I baptize you with water to repentance
Matt.3:6   They had himself in the river, the Jordan, by him baptisms
Matt.3:14 I need through You to be baptized

Since in many cases the translation of medial forms does not differ from that of active or passive forms, the abbreviation of medium (med) is added in brackets to the translation of all medial forms, including those where the medium and passivum coincide. An example can be found under word 3961 sainô "to move back and forth; to set in motion, to shock.
.1 sainesthai being shaken (med)

Since the translation of passive forms sometimes does not differ from that of active or medial forms, the abbreviation of passive (pass) is added in parentheses to the translation of all passive forms, e.g., under word 3963 saleuô "to shake, to cause to falter.
.7 saleuthçsontai they will be shaken (pass)

See further at grammar.