Greek "Howling". As a general term, "goetia" refers to low magic (as opposed to Theurgy), involving the Evocation of evil spirits in an attempt to force them to fulfil ones material wishes. As a specific term, "The Goetia" is a part of "The Legemoton, or Lesser Key of Solomon" - a grimoire (which contains goetia) translated by Macgregor Mathers and edited by Aleister Crowley, which proved to be the catalyst for their falling out.

pertaining to non-religious magickal methods or systems, hence many forms of spellcraft

Part of the Lesser Key of Solomon, this book has the names and sigils of 72 demons, 36 by day and 36 by night (whatever that means)

Typically used in reference to medieval grimoires oriented toward the summoning of various spirits, or in reference to Magick used in evocation.

Goetia refers to a practice which includes the Invocation or Evocation of demons, and usage of the term in English largely derives from the 17th century grimoire Lemegeton Clavicula Salomonis, or The Lesser Key of Solomon.