The Collaborative International Dictionary of English v.0.48:
Pertain \Per*tain"\, v. i. [imp. & p. p. Pertained; p. pr. &
vb. n. Pertaining.] [OE. partenen, OF. partenir, fr. L.
pertinere to stretch out, reach, pertain; per + tenere to
hold, keep. See Per-, and Tenable, and cf. Appertain,
1. To belong; to have connection with, or dependence on,
something, as an appurtenance, attribute, etc.; to
appertain; as, saltness pertains to the ocean; flowers
pertain to plant life.
Men hate those who affect that honor by ambition
which pertaineth not to them. --Hayward.
2. To have relation or reference to something.
These words pertain unto us at this time as they
pertained to them at their time. --Latimer.
Moby Thesaurus II by Grady Ward, 1.0:
36 Moby Thesaurus words for "pertaining":
a propos, ad rem, admissible, affinitive, appertaining, applicable,
applying, apposite, appropriate, apropos, associative, belonging,
comparable, comparative, congenial, connective, correlative,
en rapport, germane, in point, involving, linking, material,
pertinent, proportionable, proportional, proportionate, referable,
referring, relating, relational, relative, relevant, sympathetic,
to the point, to the purpose