What is the meaning of 五十音図?

the 5x10 table used for arranging all the 47 kana used for the 五十音 (literally fifty sounds), whose (columns) are arranged by the vowels (/a/, /i/, /ɯ/, /e/, /o/) and (rows) are arranged by the consonants (Ø, /k/, /s/, /t/, /n/, /h/, /m/, /j/, /ɾ/, /w/; voiced obstruents and /p/ are customarily not included because they were rarely distinguished in writing); columns are ranked by (grade), with the vowel /a/ being the highest grade and the vowel /o/ being the lowest; the missing cells of the や行 (ya-row) and わ行 (wa-row) are filled with / (i), / (e) and / (u) taken from the あ行 (a-row), in order to represent classical grammatical inflection with modern text (or alternatively, artificially filled with rare kana such as 𛀆/𛄠 (yi), 𛀁/𛄡 (ye) and 𛄟 (𛄟)/𛄢 (wu))

Source: wiktionary.org