psis

Noun

psi (countable and uncountable, plural psis)

1. (countable) The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
2. (uncountable) A form of psychic energy.
   • ‘Come, lad,’ he said. ‘We will take tea together and speak of the noumenon, the psi and other more heterogenous phenomena.’1993, Will Self, My Idea of Fun

See all 3 meanings of psi