volcanic lava occurring as rough-surfaced jagged blocks
block lava in American English
lava formed in sharp, angular, rough-surfaced blocks
block lava in American English
noun
Geology
basaltic lava in the form of a chaotic assemblage of angular blocks; aa
Word origin
[1910–15]This word is first recorded in the period 1910–15. Other words that entered Englishat around the same time include: blackout, coverage, homeroom, payoff, zing