Persian suffix اندن (-ândan) is actually, a compound suffix comprised of suffix ان (-ân) and verb-making suffix یدن. It exists both as انیدن (-ânidan) and اندن (-ândan) but the latter is more prevalent. It is used to make causative verbs. These verbs indicate “to cause to do”, “to make do”, etc. For example, tars means “fear”, tarsidan means “to fear” and its causative form tarsândan means “to frighten” i.e. “to cause somebody to be afraid, to make somebody feel afraid”.

WordDerivation
ترس
tars
fear
ترساندن
tarsândan
to frighten
جوش
juš
boiling
جوشاندن
jušândan
to make boil
خشک
xošk
dry
خشکاندن
xoškândan
to cause to become dry
رقص
raǧs
dance
رقصاندن
raǧsândan
to make dance
فهم
fahm
understanding
فهماندن
fahmândan
to make understand

All intransitive verbs can have a causative form. It is made by suffixing اندن (or انیدن) to their present stem.

VerbPresent StemCausative Form
خندیدن
xandidan
to laugh
خند
xand
خنداندن
xandândan
to make laugh
گشتن
gaštan
to turn
گرد
gard
گرداندن
gardândan
to cause to turn
خوردن
xordan
to eat
خور
xor
خوراندن
xorândan
to cause to eat