Definition:Conjugate Axis of Hyperbola/Also defined as

Conjugate Axis of Hyperbola: Also defined as

Some sources do not consider the minor axis of a hyperbola separately from the conjugate axis, and instead define the conjugate axis as the infinite straight line that coincides with it.

From D.M.Y. Sommerville: Analytical Conics (3rd ed.):

There is no minor axis, but the other axis of symmetry, the $y$-axis, is called the conjugate axis.

However, on $\mathsf{Pr} \infty \mathsf{fWiki}$ we prefer to keep the concepts separate.

Some sources use the term conjugate axis to mean any arbitrary line segment on the minor axis.

Sources

• 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text {V}$. The Hyperbola: $2$.
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): conjugate axis
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): hyperbola
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): conjugate axis
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): hyperbola
• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): conjugate axis
• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): hyperbola