The Collaborative International Dictionary
Seldom \Sel"dom\ (s[e^]l"d[u^]m), adv. [Usually, Compar. More seldom (m[=o]r" s[e^]l"d[u^]m); superl. Most seldom (m[=o]st" s[e^]l"d[u^]m); but sometimes also, Seldomer (s[e^]l"d[u^]m*[~e]r), Seldomest.] [AS. seldan, seldon, seldum, fr. seld rare; akin to OFries. sielden, D. zelden, G. selten, OHG. seltan, Icel. sjaldan, Dan. sielden, Sw. s["a]llan, Goth. sildaleiks marvelous.] Rarely; not often; not frequently.
Wisdom and youth are seldom joined in one.
--Hooker.
Usage examples of "most seldom".
Franklin must learn to use a whole armory of tools and weapons: borers to collect specimens of the sea bed, meters to check the efficiency of the fences, sampling devices, branders for painlessly marking un-co-operative whales, electric probes to discourage marine beasts that became too inquisitive-and, most seldom used of all, the tiny torpedoes and poisoned darts that could slay in seconds the mightiest creatures of the seas.
He told me that he'd found most of what he needed, but he said my shop was the only one with a complete selection of even the most seldom-used ingredients for spells and incantations.