An Etymological Dictionary of Astronomy and Astrophysics

1. Of or relating to a matter of importance.
   

   2. Having important or dangerous possible consequences.

Etymology (EN): From M.E., from O.Fr. serios “grave, earnest” and directly from Late L. seriosus, from L. serius “weighty, important, grave,” probably from a PIE root *swer- “slow, heavy;” cf. Lith. sveriu, sverti “to weigh, lift,” svarus “heavy, weighty;” O.E. swaer “heavy,” Ger. schwer “heavy,” Gothic swers “honored, esteemed,” literally “weighty”).

Etymology (PE): Padel, from Balôci padel “serious,” of unknown origin.