What does ‘the Way, the Truth, and the Life’ mean in Christianity? The Way is fairly straightforward from the context, it means ‘the way to the Father’, i.e., to God.
The Truth is more tricky. Nowadays, people often equate truth with objects, their location in space, their momentum, and so on. Jesus here is referring to spiritual truth. It is about proper action, values, and relates to meaning or purpose. This is a more ancient notion of truth, and is related to reliable systems for guiding us in our actions. The idea here is that Jesus teaches spiritual truth, and also embodies this truth in his actions.
The Life again means spiritual life. “I have come so you may have life and have it fully.” The obvious connotation here is eternal life, but it is not just life, rather full life. Jesus is the path to full and eternal life, and also embodies it in his own life story (with the resurrection). Full and eternal life comes, at root, from a relationship with the Father, according to Christianity. Jesus is the link between us and the Father, offering us his teachings, his example, and the precedent of his own death and resurrection, which changes on a fundamental level the possibilities for other people, according to Christianity.