a branch of the Indo-European family of languages, including especially Irish, Scottish Gaelic, Welsh, and Breton, which survive now in Ireland, the Scottish Highlands, Wales, and Brittany. adjective. 2. of the Celts or their languages.
Movement of tectonic plates-higher. Volcanoes, mountains and earthquakes occur at the edges of tectonic plates-their creation depends on the direction the plates are moving.
Three processes that contribute to the motion of tectonic plates  are convection currents, ridge push, and slab pull. Convection  currents is when the mantle rises, cools, sâ¦inks and heats, then  rises and repeats the cycle. Ridge push is a gravitational force  that causes a plate to move.