pentode pentobarbital • pentoic · · · Info · Definitions · Characters · · pentode · · Text Latin · · Script 7 · · Length Definitions · · · (noun) a thermionic tube having five electrodes. · · Noun Definition 1 Characters · · d latin small letter d U+0064 e latin small letter e U+0065 n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 t latin small letter t U+0074