Elevation

Description
Elevation is the process of a word's meaning taking a more positive definition over time; it is also called amelioration.

Examples
An example of amelioration is the word priest. At first, it meant "old man" since it is often thought that age is accompanied by wisdom and most religions were lead by elders and not youth. Eventually, this Greek word acquired the definition of "church leader". The word has gone through different changes over time, the oldest English form being priest, followed by prester, followed by the learned borrowing of presbyter.

Nice:At first, nice appeared in Middle English and meant "foolish, silly, simple, ignorant senseless and absurd; describing a person or thier actions." Around the 1500s the word began to change its connotation to "requiring or involving great precision or accuracy." It reached the definition "kind and considerate;friendly," around the 1800s.

Brave: Brave used to mean "uncivilized", long before attaining nobility

Fame: Originally the word fame meant "a report; either good or bad"; now, of course, it means "a good report."

Lord: The word lord comes from a conotation of the Anglo-saxon words "loaf" and "guard", therefore meaning "bread keeper", as time passed through the word, it reached the exalted title it refers to today.

Senile :(SEN- = "old") has mostly been used to describe the worst charasteristics of old age, but on the word "senate" it highlights the best charasteristics of old age, "wisdom and mature judgement".