[ ˌʌɪkɒsəˌpɛnti:'nəʊɪk ]
■ noun Chemistry a polyunsaturated fatty acid found especially in fish oils.
Origin
1960s: from Gk eicosa- 'twenty' (the number of carbon atoms in the molecule) + penta- 'five' (the number of unsaturated bonds) + -ene + -oic on the pattern of methanoic .