arachnomancy

From arachno- +‎ -mancy.

arachnomancy (uncountable)

1. The study of the appearance and behavior of spiders, or the patterns of their webs (possibly related to the third meaning) for use in divination.
2. The ability to take control over spiders with the intent to use them for attacking or similar purposes.
3. The divination of patterns, for example in geometric patterns and tapestries.

• 2004, The Review of the film ‘Sodoma's Ghost’, MonsterHunter:

  I suppose I should save my arachnomancy for another time, since you may yet not be convinced that horny Nazi ghosts bothering drunk college kids isn't really nearly as good as you would initially suspect

• Night Club, Howl Grimm

  Howl allowed the spider to climb up her arm and settle on her shoulder. Howl was well practiced in arachnomancy, and this spider would be useful in her divining.

  She sighed deeply and extended her hand, 'Apology accepted, Alanna.'

• arachnomancer (noun)

• “arachnomancy”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.