from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Not distinguishable, especially:
- adj. Impossible to differentiate or tell apart: indistinguishable twins; markings that make a moth indistinguishable from its background.
- adj. Impossible to discern; imperceptible: a sound that was indistinguishable to the human ear.
- adj. Difficult to understand or make out; vague: indistinguishable speech.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Not distinguishable; not capable of being perceived, known, or discriminated as separate and distinct
- adj. Not capable of being perceived or known.
from the GNU version of the Collaborative International Dictionary of English
- adj. Not distinguishable; not capable of being perceived, known, or discriminated as separate and distinct; hence, not capable of being perceived or known
from The Century Dictionary and Cyclopedia
- Not distinguishable; incapable of being distinguished, separated, or discriminated.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. not capable of being distinguished or differentiated
- adj. exactly alike; incapable of being perceived as different
in- + distinguishable (Wiktionary)