| Blue (superl.) Having the color of the clear sky, or a hue resembling it, whether lighter or darker |
| Blue (superl.) Pale, without redness or glare, -- said of a flame |
| Blue (superl.) Low in spirits |
| Blue (superl.) Suited to produce low spirits |
| Blue (superl.) Severe or over strict in morals |
| Blue (superl.) Literary |
| Blue (n.) One of the seven colors into which the rays of light divide themselves, when refracted through a glass prism |
| Blue (n.) A pedantic woman |
| Blue (pl.) Low spirits |
| Blue (v. t.) To make blue |
| blue wall of silence / blue wall / wall of silence the secrecy of police officers who lie or look the other way to protect other police officers, "the blue wall cracked when some officers refused to take part in the cover-up" |
| cyanobacteria / blue-green algae predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll, occur singly or in colonies in diverse habitats, important as phytoplankton |
| bonito shark / blue pointed / Isurus glaucus common blue-grey shark of southwest Pacific, sport and food fish |
| blue shark / great blue shark / Prionace glauca slender cosmopolitan, pelagic shark, blue body shades to white belly, dangerous especially during maritime disasters |
| blue jay / jaybird / Cyanocitta cristata common jay of eastern North America, bright blue with grey breast |
| blue mockingbird / Melanotis caerulescens mockingbird of Mexico |
| blue tit / tomtit / Parus caeruleus widely distributed European titmouse with bright cobalt blue wings and tail and crown of the head |
| blue-headed vireo / Vireo solitarius solitarius common vireo of northeastern North America with bluish slaty-grey head |
| Cooper's hawk / blue darter / Accipiter cooperii bluish-grey North American hawk having a darting flight |
| western fence lizard / swift blue-belly / Sceloporus occidentalis common western lizard, seen on logs or rocks |