Tehillah means praise, song of praise, or hymn. It appears about 60 times. It is the root of 'hallelujah' (praise Yah). The book of Psalms in Hebrew is Tehillim (Praises). It describes worship directed to God.
Praise is the vocation of God's people. 'You are a chosen people... that you may declare the praises of him who called you' (1 Peter 2:9). Heaven is filled with tehillah. Israel exists 'for the praise of His glory' (Ephesians 1:12). Praising God is both present worship and eternal destiny.