Astride

with a leg on each side of; straddling:
She sat astride the horse.
on both sides of:
Budapest lies astride the river.
in a dominant position within:
Napoleon stands astride the early 19th century like a giant.
in a posture of or straddling; with legs apart or on either side of something.
Contemporary Examples

Still worse to imagine that we’d be doing all this while rolling around town on a Schwinn, rather than astride our majestic steed.
Where are the Bicycles in Post-Apocalyptic Fiction? Megan McArdle January 27, 2013

Director Ridley Scott, however, must have found the image of Cameron Diaz astride a gleaming sports car too good not to show.
The Best Scenes From Cormac McCarthy’s ‘The Counselor’ Screenplay Thomas Flynn October 26, 2013

Historical Examples

Besides, the silent man behind was astride the better animal.
Bob Hampton of Placer Randall Parrish

I got astride of the buttress, and painfully forced my way up.
Wilfrid Cumbermede George MacDonald

Cliffe looked at the small figure a moment, then seized a chair and sat down in front of her, astride.
The Marriage of William Ashe Mrs. Humphry Ward

From the window of my room I saw the doctor get astride his mule.
The Strolling Saint Raphael Sabatini

Sandy helped the laird to the horse, and boosted him up astride.
Jokes For All Occasions Anonymous

Every one was afoot or astride a pony, for there was nothing on wheels, not even a barrow.
A Wayfarer in China Elizabeth Kendall

Both guns quickly stopped the rush, but not before three men were astride the concrete wall.
A Lively Bit of the Front Percy F. Westerman

If you had seen me get astride of a plank, would you have remained on land, Porthos?
The Man in the Iron Mask Alexandre Dumas, Pere

adjective (postpositive)
with a leg on either side
with the legs far apart
preposition
with a leg on either side of
with a part on both sides of
adv.

1660s, from a- (1) “on” + stride (n.).