main spindle; main shaft
linchpin; pivot
《mathematics》principal axis; main axis
彼が打線の主軸を担う。
He serves as the linchpin of the batting lineup.
新事業戦略の主軸は市場開拓にある。
The core of the new business strategy lies in market development.
山田氏は3年間の共同研究プロジェクトの主軸を務める。
Mr. Yamada serves as the main axis of the three-year joint research project.