Farāʾiḍ

The Qur'anically fixed inheritance shares — 1/2, 1/4, 1/8, 2/3, 1/3, 1/6.

ʿAṣabah

Residual heirs — those who inherit what remains after the fixed shares are paid, typically male agnatic relatives.

ʿAwl

Proportional reduction of shares when the total of fixed shares exceeds the estate.

Radd

Return — increasing the fixed-shareholders' shares proportionally when the total of fixed shares is less than the estate and there is no ʿaṣabah.

Waṣiyyah

A bequest — up to one-third of the estate may be willed to non-heirs or charitable causes.