Tacahout
or TACOUT, the name of small, irregularly-rounded, tuberculate galls produced by a species of cynips on the twigs of a tamarix (probably T. articulata) in Algeria and Morocco.
They contain a large quantity of gallic acid, and are used in photographic prep- TACITUS arations. The above-named species of tamarix, as also T. gallica and T. dioica, supply a similar gall in India-the mahi of the Punjab and sakun of Sindh; used as a mordant in dyeing and in tanning.