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 "more seldom".
And to Isengard the emissaries from Minas Tirith came ever more seldom, until they ceased.
She screamed in the cellar, but I couldn't see why she was screaming, for the cellar transom, through which potatoes were poured on delivery days, but more and more seldom in the war years, was also closed.
I now make entries in this diary much more seldom than I used to, for the reason that I literally have not any spare time.
The restaurant occupied almost all of the street front of the ground floor, a blank, non-committal double doorway at one extreme of its plate-glass windows was seldom open and even more seldom noticed.
She appeared more seldom in 1887-1889, and by 1892 even the light footsteps ceased.