indistinction

First attested in 1624; formed as in- +‎ distinction, after indistinct.

• (Received Pronunciation, UK) enPR: ĭndĭstĭngkʹshən, IPA^(key): /ɪndɪˈstɪŋkʃən/

indistinction (countable and uncountable, plural indistinctions)

1. The fact of not distinguishing or making distinctions; failure to perceive or make a difference.
2. The condition or fact of not being distinct or different; absence of distinguishing qualities or characteristics; undistinguishableness.
3. (obsolete) Indistinctness, obscurity, dimness.
4. (nonce use) Absence of distinction or eminence; obscurity.

• “Indistinction” listed on page 221 of volume V (H–K), § ii (I) of A New English Dictionary on Historical Principles [1st ed., 1901]
• “indistinction” listed in the Oxford English Dictionary [2nd ed., 1989]