What does "broadening" refer to?

Broadening refers to the phenomenon where a word's meaning expands to encompass a wider range of contexts than it originally had. This process allows the word to be applied in more situations, thus increasing its usage and versatility in the language. For example, the word "holiday," which once specifically referred to a religious observance, now is commonly used to describe any day of leisure, particularly those spent away from work or school.

The other choices do not accurately capture the essence of broadening. The first option describes a more specific usage, which is related to narrowing rather than broadening. The third option talks about obsolescence, which describes a word falling out of use rather than expanding its meaning. Finally, the fourth option refers to a dramatic shift in meaning, which could also imply narrowing or other semantic changes rather than the specific process of broadening.