GOV.WALES uses cookies which are essential for the site to work. Non-essential cookies are also used to tailor and improve services. By continuing to use this site, you agree to our use of cookies.
You are here:
Noun, Masculine, Singular
hanner oesau
Yr amser a gymer ymbelydredd isotop penodol i ddadfeilio i hanner y gwerth gwreiddiol.
Yng nghyd-destun ymbelydredd.