On the assumption that you are in senior HS or college level of understanding, because the term is hardly an elementary subject matter, I will start from general to specific description of the term,
It is an ORGANIC salt ( note: not all salts are inorganic like NaCl), composed of the (negative) anion Chloride (Cl-) and an organic (positive) cation, dimethyl ethyl benzyl ammonium ion.
Remember the ammonium ion NH4+. This is nitrogen bonded to 4 hydrogens. Now, in dimethyl, ethyl, benzyl ammonium, the four H's are replaced by one methyl (CH3) group, another methyl group, one ethyl (C2H5 ), and benzyl (CH2 -C6H5). It is hard to put the formula here but it is similar to
[ (CH3)2 - N - C2H5]+ [Cl-]
The CH2-C6H5 is under the middle nitrogen and within the brackets. Refer to organic chem text. And because organic groups have replaced 4 H's, it is a QUARTERNARY Ammonium salt. (Tertiary is only 3 H's are replaced, etc)
Because methyl, ethyl and benzyl are organic groups, then it is an organic salt.
It is used as a bathroom cleaner or disinfectant. It has anti-bacterial property.