| deep white layer of superior colliculus | See: gray layer of superior colliculus. (05 Mar 2000) |
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| deepen | To become deeper; as, the water deepens at every cast of the lead; the plot deepens. "His blood-red tresses deepening in the sun." (Byron) Source: Websters Dictionary (01 Mar 1998) |
| deepwater habitat | <ecology, marine biology> Any open water area in which the mean water depth exceeds 6.6 feet at mean low water in nontidal and freshwater tidal areas, or is below extreme low water at spring tides in salt and brackish tidal areas, or the maximum depth of emerging vegetation, whichever is greater. (09 Oct 1997) |