parenthesis-free
/pəˌrɛnθɪsɪsˈfriː/Logic and Computing
adjective
Designating a notation which eliminates the need for parentheses, especially that of the Polish logician Jan Łukasiewicz (1878–1956); written using such a notation.
Origin
1930s; earliest use found in Journal of Symbolic Logic. From parenthesis + free.