(b). DUON- also denotes relationship by marriage, and is also a prefix in such words as duonpago = half-pay, duonjara = half-yearly, etc. As a root, duono = a half, so properly it should signify only half-blood relationship. As, however, there are few relationships of this nature, it is used also for step relationship, as:—Duonfrato = stepbrother or half-brother.
(c). GE- denotes both sexes taken together. The words are always in the plural, and the feminine suffix is, of course, never added.
Examples.—Edzo = a husband, geedzoj = husband and wife, a married couple. Sinjoro = Sir, Mr., gesinjoroj = Mr. and Mrs., or, ladies and gentlemen. Patro = father, gepatroj = father and mother, parents. Mastro = a master (of a household), gemastroj = master and mistress. Frato = brother, gefratoj = brother(s) and sister(s).
(d). PRA- denotes great distance of time, past or future. As regards relationship, it is the equivalent of the English prefixes "fore-," "great," or "grand." As a root, praa = primeval.
Examples.—Pratempo = primitive time. Praarbarego = primeval forest. Prapatroj = forefathers, ancestors. Praonklo = grand, or great, uncle. Praavino = great-grandmother.
(e). The following are examples of these four prefixes:—
Patro = father, bopatro = father-in-law, duonpatro = stepfather, gepatroj = father and mother, parents.
Patrino = mother, bopatrino = mother-in-law, duonpatrino = stepmother.
Avo = grandfather, boavo = grandfather-in-law, duonavo = stepgrandfather, geavoj = grandparents, prageavoj = great-grandparents.
Filo = son, bofilo = son-in-law, duonfilo = stepson.