C19: from Medieval Latin summandus, from Latin summasum1
summand in American English
(ˈsʌmænd, sʌmˈænd, səˈmænd)
noun
a part of a sum
Word origin
[1890–95; ‹ ML summandus, ger. of summāre to sum]This word is first recorded in the period 1890–95. Other words that entered Englishat around the same time include: blanket roll, blip, cholesterol, historicism, masochism