Definition of parenthesis-free in English:

parenthesis-free

Pronunciation /pəˌrɛnθɪsɪsˈfriː/

adjective

Logic Computing
  • 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.