When an idea or concept starts to become clearer or more defined, it "takes shape." There are various synonyms for this phrase that could be used to convey this meaning. For example, the concept could "crystallize" or "materialize" as clarity emerges. Additionally, an idea could "solidify" or "coalesce" as it becomes more substantial. Furthermore, the concept could "emerge" or "develop" as it takes shape into something more concrete. Overall, there are many synonyms to choose from when describing an idea taking shape, each with their own nuances and implications.