Monotony (noun)

1. The state or quality of being dull, tedious, or repetitious.
2. The repetition of a single thing or action many times, leading to boredom or lack of interest.

Origin:

From the latin 'monotonia' meaning 'sameness, monotony'.

Examples:

1. The monotony of the work was getting to her.
2. The monotony of the long journey was broken by the scenery.
3. The monotony of the lecture put many students to sleep.
4. The monotony of the routine was broken by a change of pace.
5. The monotony of the day was broken by a phone call from an old friend.