surprisal
noun/sə(ɹ)ˈpɹaɪzəl/
Etymology From surprise + -al. (information measure): Defined by Myron Tribus in the 1961 book Thermostatics and Thermodynamics.
1
Government, Military, Politics, War Obsolete A surprise attack or ambush; a sudden or unexpected assault.
- Their chiefe attempts are by Stratagems, trecheries, or surprisals.1624, John Smith, Generall Historie, Kupperman, published 1988, page 146:
2
Obsolete A sudden coming-upon someone or something unexpectedly or unawares.
- How to secure the lady from surprisal1646 (indicated as 1645), John Milton, “Comus”, in Poems of Mr. John Milton, […], London: […] Ruth Raworth for Humphrey Mosely, […], →OCLC:
- Because death is uncertain, let us prevent its surprisal.a. 1678 (date written), Isaac Barrow, “(please specify the chapter name or sermon number)”, in The Works of Dr. Isaac Barrow. […], volume (please specify |volume=I to VII), London: A[braham] J[ohn] Valpy, […], published 1830–1831, →OCLC:
3
Obsolete A surprising event or occurrence.
4
Obsolete The feeling caused by being surprised; surprise, shock, amazement.
5
An information measure as equal in bits (binary digits) to the base-2 log of 1 over the probability, with the result that the number of choices equals 2ⁿ where n is the number of bits.
- Because language is produced and processed over time, we get it bit by bit. This allows a measure of the goodness of an incoming word according to how expected it was, given the preceding context: its expectedness or surprisal. Surprisal and expectedness are inverses: When an incoming word is highly expected, its surprisal is close to zero.2025, Edward A. F. Gibson, “Preliminaries: Components of Language Structure” (chapter 2), in Syntax: A Cognitive Approach, MIT Press, →DOI, →ISBN, pages 23–24: