IIgnimbrites are pumice-dominated pyroclastic flow deposits with subordinate ash.There are
many historic examples, most of which are restricted to valleys emanating from summit craters.
One such deposit from the 1980 eruption of Mt. St. Helens (below left) contains abundant
pumice blocks at its terminus. However, there are no historic examples of the voluminous
ignimbrite sheetflows associated with caldera formation. These extensive deposits can cover
many thousands of square kilometers. They often appear as coherent, well-compacted, often
partially welded, layers that in some cases resemble lava flows, as demonstrated by the Miocene

I couldn't find a good definition, but it appears that illocution is speech intended to secure
a action or result desired by the speaker.
Illocutionary force distinguishes the following types of acts:

Asserting
Promising
Excommunicating
Exclaiming in pain
Inquiring
Ordering

Imparlance (Page: 733)

Im*par"lance (?), n. [Cf. Emparlance, Parlance.] [Written also inparliance.]

1. Mutual discourse; conference. [Obs.]

2. (Law) (a) Time given to a party to talk or converse with his opponent, originally with the
object of effecting, if possible, an amicable adjustment of the suit. The actual object, however,
has long been merely to obtain further time to plead, answer to the allegations of the opposite party.
(b) Hence, the delay or continuance of a suit. &hand; Imparlance and continuance by
imparlance have been abolished in England. Wharton (Law Dict. ).

Not to be confused with elocution...

An Introduction to Yoga, by Swami Krishnananda
.. none of these four visible elements is really the hard or impartite thing that ...
reality,--let us be contented just now with the scientific definition of reality ...
www.swami-krishnananda.org/intro/intro_03.html

From the Oxford Dictionary of English Grammar:

illocution
Linguistics. An act effected by a speaker by the very fact of making an utterance, in that the stating, inquiring, requesting, commanding, or inviting itself constitutes an action; the communicative function of an utterance.

illocutionary (for illocutionary force, see the quotation of 1955)

The term derives from J. L. Austin's Speech-Act Theory, where it contrasts with LOCUTION (the act of making a referentially meaningful utterance) and PERLOCUTION (concerned with an addressee's response to the speaker's illocution). It is thus central to discussions of the social and interpersonal meaning of language behaviour, and has gained wider currency than the other two terms.

Bingley

Thanks, Bingley. I suppose recency of coinage is why so many dictionaries didn't have it.
As a sour jest, I'm reminded of music critic's reply to fond mother who badgered him for
an opinion of her pianist daughter's "execution" to which he replied he was in favor of it.

Most have more recent coinages than 1955, don't they?

Bingley

I guess 1955 seems more recent to me than is should. I can remember so much before that.