Below the age of 20, acne can cause dark spots due to scarring and red marks left by the infection. Skin Diseases That Cause Dark Spots Melasma: Itâs one of the commonest causes of grayish patches on the face. It mostly affects the forehead, cheeks, or the area between your mouth and nose.
The definition of a titter is a nervous and half-hidden laugh. An example of a titter is the laugh made by a schoolgirl in class. verb. To titter means to laugh or giggle in a somewhat suppressed way. An example of to titter is the laugh of a nervous toddler.
Titrimetry refers to that group of analytical techniques which takes advantage of titers or concentrations of solutions. In metallurgy the word titer refers to the fineness of gold or silver. In chemistry it is the measure of the concentration of a solution. In medicine it is defined as the extent to which an antibody solution can be diluted before it ceases to give a positive reaction with an antigen.