God's Lord, literally. "Lord of God". It appears in the Latin Mass, "Sanctus, Sanctus, Sanctus, Dominus Dei Sabaoth..." and is usually translated as "Holy, holy, holy, Lord God of hosts..."
The English meaning of the Latin word 'tecum' is With you. In the word-by-word translation, the personal pronoun 'te' means 'you' in the singular form. The preposition 'cum' means 'with'.