Familiarity (noun)

1. The state or quality of being familiar; knowledge or experience of a thing or situation.
2. The state of being on familiar terms; intimacy.
3. The state or quality of being too casual or informal.

Origin:

Middle english: from old french familiarite, from latin familiaritas, from familiaris (see familiar).

Examples:

1. With familiarity comes understanding.
2. He achieved familiarity with the subject.
3. She achieved familiarity with the task.
4. He had a familiarity with the language.
5. She had a familiarity with the culture.