General:
* Troposphere: The lowest layer of the Earth's atmosphere, characterized by temperature decreases with altitude. This is because the air turns over and mixes.
* Tropic: Relating to the tropics, a region that circles the Earth near the equator, where the sun's rays are most direct. This term derives from the Greek word "trope" meaning "turn" because the sun's path appears to "turn" around at these latitudes.
Scientific:
* Tropism: The growth of a plant or other organism in response to an external stimulus, such as light or gravity. This refers to the "turning" of the organism's growth direction.
* Tropotaxis: The directed movement of an organism in response to a stimulus. This refers to the "turning" of the organism's movement direction.
* Troponin: A protein found in muscle tissue that helps to regulate muscle contraction. It plays a key role in the "turning on" and "turning off" of muscle contractions.
Other:
* Trope: A figure of speech that uses figurative language. This is a metaphorical "turning" of words to create a new meaning.
* Tropaeolum: A genus of flowering plants, commonly known as nasturtiums. The name comes from the Greek word "tropaion" meaning "trophy" or "turning point," possibly referring to the plant's use as a symbol of victory.
Note: The root "tropo" can also be used in a broader sense to indicate change, movement, or transformation. For example, the word "tropopause" refers to the boundary between the troposphere and the stratosphere, where there is a change in atmospheric conditions.