Which term means to emphasize or actualize an idea into reality?

The term that means to emphasize or actualize an idea into reality is "realise." When you realize something, you not only recognize or understand it conceptually, but you also bring it into a tangible form or make it manifest in the real world. This aligns perfectly with the notion of taking an abstract idea and turning it into something concrete.

In contrast, the other choices do not capture this idea of actualizing an idea into reality. To modify means to change something, which does not necessarily imply realizing it. Recall refers to retrieving information from memory, and while propose involves suggesting an idea, it does not involve making that idea a reality. Thus, the term "realise" is specifically tied to the act of bringing ideas to fruition, making it the most suitable choice.