precover

== English == === Etymology 1 === From pre- +‎ cover. ==== Noun ==== precover (plural precovers) (mathematics) A generalization of a cover in which the kernel may contain a non-zero pure subgroup. Something that occurs in preparation for a covering. === Etymology 2 === From pre- +‎ discover. ==== Verb ==== precover (third-person singular simple present precovers, present participle precovering, simple past and past participle precovered) (astronomy) To find an older image of an object in archived images after it has been discovered. ===== Related terms ===== precovery