As a noun isdn is
(telecommunications|initialism).
ismn
Not English
Ismn has no English definition. It may be misspelled.
English words similar to 'ismn':
icon,
ikon
isdn
English
Noun
(
en noun)
(telecommunications, initialism) .
(chemistry, initialism) .
See also
* (telecommunications) BRI , PRI
Anagrams
*