adjective Etymology: irregular from New Latin Pennales Date: 1938 of, relating to, or being usually elongate bilaterally symmetrical diatoms of an order (Pennales) having a raphe or a similar structure
PENNATE
Meaning of PENNATE in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012