Which word means to nurse something to life or activity?

The term that means to nurse something to life or activity is "foster." To foster something involves nurturing or supporting its development or growth, similar to how one would support the progress of a child or an idea. This term is frequently used in contexts where encouragement is provided to help something flourish or become more active.

In contrast, while "foment" can suggest instigating or promoting growth, particularly in a more abstract or sometimes negative context, it does not encapsulate the concept of nurturing or caring for something to bring it to life as effectively as "foster."

"Encourage" implies providing support or confidence but lacks the specific connotation of nurturing growth or formation. "Stimulate" suggests provoking or boosting activity but does not inherently connote the process of nurturing, which conveys a deeper level of care and involvement.

Thus, "foster" accurately reflects the nuance of nurturing something into life or greater activity, making it the most appropriate choice.