There are three meanings of the word ‘truth’:
1. The dictionary meaning of truth is ‘what is real’.
2. Second meaning of truth is ‘when our speech and actions are the same as our thoughts’.
3. In Véd-s ‘Truth’ means what is real today, what was the same yesterday, a hundred years ago, and even a billion years ago; what will be the same tomorrow, a hundred years from today, and even a billion years from now. In other words, something that does not change over time. That ‘Truth’ is changeless, beginning-less, and endless. It is the description of Paramātmā (Brahman, God, the Supreme Power). Not everyone believes in ‘God’ and that view is acceptable in Védic tradition too.
The first two Truths (1 and 2) are to be practiced. The third is a goal to be achieved by becoming an ideal person. Different interpretations of the word ‘Truth’ can be confusing.