pec·tic acid 
(pĕktĭk)
(pĕktĭk)n.
Any of several transparent gelatinous acids that are insoluble in water and are formed by partial or complete hydrolysis of certain esters of pectin.
[French pectique, related to pectin, from Greek pēktikos, coagulating, from pēktos, coagulated; see PECTIN.]