Talk:obscura

The etymologies for inflectional endings are:

1. nominative and vocative singular feminine: PIE *-eh₂ (late PIE feminine marker) > Old Latin -ā > Classical Latin -a
2. NAV neuter plural: PIE *-eh₂ (originally used to form collective nouns, but distinct than the previous suffix)
3. ablative singular: Old Latin -ād (formed analogically to o-stem ending -ōd, which later yielded Classical Latin -ō) > Classical Latin > -ā

More information on PIE endings can be found on the unfinished appendix: Appendix:PIE declension.
obscurus is an old word containing a Proto-Indo-European root that has not been transparently preserved in other Latin words (there are culus and cutis, both without the s-mobile s- and with different suffixes). Its inflection as a distinct adjective dates probably to Proto-Italic or late PIE. --Ivan Štambuk 08:27, 12 June 2010 (UTC)

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wikisource:en:The fairy tales of science/The Magic of the Sunbeam