hína noun "child", also hina used in the vocative to a (young) child (also hinya "my child", for hinanya) (WJ:403). Pl. híni (surprisingly not **hínar) in Híni Ilúvataro "Children of Ilúvatar" (Silmarillion Index); dative hínin in VT44:35. In compounds -hin pl. -híni (as in Eruhíni, "Children of Eru", SA:híni). According to one source, the word is hín(i) and solely plural (PE17:157), but this is obviously contradicted by some of the sources quoted above.
@@@ a more accurate gloss might be “offspring”, as suggested by Tamas Ferencz: plus.google.com
onwë noun "child" (PE17:170)
selda adj.?noun? (meaning not clear, related to seldë "child" (meaning changed by Tolkien from "daughter") and seldo "boy". Thus selda may be an adjective "childlike", since -a is a frequent adjectival ending. Alternatively, as suggested in VT46:13, selda may be a neuter noun "child", corresponding to masc. seldo "boy" and fem. seldë "girl" (before Tolkien changed the meaning of the latter to "child"). (SEL-D, cf. VT46:22-23)
seldo noun (meaning not quite clear, likely the masculine form of seldë "child", hence *"boy") (SEL-D, VT46:13, 22-23)
seldë noun "child" (meaning changed by Tolkien from "daughter"; in his later texts the Quenya word for "child" is rather hína, and the final status of seldë is uncertain. See also tindómerel.) (SEL-D, VT46:13, 22-23) In one late source, Tolkien reverts to the meaning "daughter", but this may have been replaced by anel, q.v.