1. A long, narrow, generally shallow receptacle for holding water or feed for animals. 2. Any of various similar containers for domestic or industrial use, such as kneading or washing. 3. A gutter under the eaves of a roof. 4. A long, narrow depression, as between waves or ridges. 5. A low point in a business cycle or on a statistical graph. 6. An elongated region of relatively low atmospheric pressure, often associated with a front. 7. A minimum point in a wave or an alternating signal.