Unfertilised

Bacteria may on average add convert nitrogen per acre, and in an unfertilised field, this is the most important source of usable nitrogen.

In the eusocial Hymenoptera, the workers are exclusively female: males (drones) are haploid and develop from unfertilised eggs, while females (both workers and the queen) are diploid and develop from fertilised eggs.

Iran bans sperm donation but allows donation of both fertilised and unfertilised eggs.

The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilised state).

This also happens in salamander eggs, even when they are unfertilised.