Rhifnod, n. a numeral
Rhifnodol, a. numerical
Rhifnodiad, n. numeration
Rhifo, Rhifnodi, v. to numerate, to number, to count, to reckon
Rhifol, a. numeral, numerical
Rhifyddeg, n. arithmetic
Rhifyn, n. a single number
Rhifyddiaeth, n. numeration
Rhiff, n. what divides or parts
Rhifft, n. what is divided, a rift