One verse

Srimad Bhagavatam 3.11.7

3.11.7

निमेषस्त्रिलवो ज्ञेय आम्नातस्ते त्रय: क्षण: । क्षणान् पञ्च विदु: काष्ठां लघु ता दश पञ्च च ॥ ७ ॥

nimesas tri-lavo jneya amnatas te trayah ksanah ksanan panca viduh kastham laghu ta dasa panca ca

nimesah
the duration of time called a nimesa
tri-lavah
the duration of three lavas
jneyah
is to be known
amnatah
it is so called
te
they
trayah
three
ksanah
the duration of time called a ksana
ksanan
such ksanas
panca
five
viduh
one should understand
kastham
the duration of time called a kastha
laghu
the duration of time called a laghu
tah
those
dasa panca
fifteen
ca
also.

The duration of time of three lavas is equal to one nimesa, the combination of three nimesas makes one ksana, five ksanas combined together make one kastha, and fifteen kasthas make one laghu.