Trikaya is a Sanskrit word used in the Buddhist context to refer to levels of manifestation or activity.
Tri means three and Trikaya as a concept concerns three levels of buddhahood.
Shakyamuni, the historical Buddha who is generally considered one of many buddhas to have come to the help of sentient beings, is understood to be accessible in various ways. These are called the dharmakaya, samboghakaya, and nirmanakya.
They have been translated into English as: truth-body, bliss or enjoyment-body, and activity-body.