Translation guide
The Japanese abacus is called そろばん. It is still used for calculation and education. The English word 'abacus' can also refer to the top part of a column in classical architecture, but that meaning is rare and technical.
abacus (Japanese)
Referring to the traditional Japanese counting frame with beads.
The standard word for the Japanese abacus. It is a common tool taught in schools.
I learned abacus when I was a child.
He is good at the abacus.
Kanji form of そろばん. Rarely used in modern writing; the kana form is standard.
The abacus was introduced from China.
Referring to abacuses from other cultures or in a generic sense.
Even for non-Japanese abacuses, そろばん is commonly used. To specify a Chinese abacus, you can say 中国のそろばん.
The Chinese abacus has a different number of beads.
Loanword from English. Used mainly in technical or historical contexts to distinguish from the Japanese そろばん.
Referring to the flat slab on top of a column capital in classical architecture.
Technical term in architecture. Not commonly known outside of specialized fields.
There is an abacus on top of the Doric capital.
In almost all everyday situations, そろばん is the correct word. The loanword アバカス is rarely needed unless you are specifically contrasting with non-Japanese types in an academic context.
An ancient Roman abacus is on display.