Definition of "stronghold"

AFter this victory thus opteyned by the Sicambris, they waxed so stronge that they wan frome ye Almaynes dyuers Townes & stronge holds wtin Germania, and after that they opteyned ye famous Cytie named Treueris; which as wytnessyth ye Auctour of Cronica Cronicaruin, was firste foundyd in the Towne of the Patryarch Abraham before the Incarnation of Criste.

a. 1513, Robert Fabyan, Henry Ellis, “Gallie Prouincia”, in The New Chronicles of England and France, in Two Parts; [...] Named by Himself the Concordance of Histories. Reprinted from Pynson’s Edition of 1516. The First Part Collated with the Editions of 1533, 1542, and 1559; and the Second with a Manuscript of the Author’s Own Time, as well as the Subsequent Editions: Including the Different Continuations. To which are Added a Biographical and Literary Preface, and an Index, volume V, London: F. C. and J. Rivington [et al.], published 1811, pars quinta [part V], capitulum lxxvii, page 56

For security's sake they [the Germans] gathered together in villages and cities. These they surrounded with heavy walls and towers, and protected them by castles, erected on steep cliffs and mountains. The custody of these strongholds was entrusted to the most efficient warriors, who in time formed a separate class, the nobility, from which the heads of the whole nation, the princes, kings and emperors were chosen.

1919, Rudolf Cronau, “Women during the Middle Ages”, in Woman Triumphant: The Story of Her Struggles for Freedom, Education and Political Rights: Dedicated to All Noble-minded Women by an Appreciative Member of the Other Sex, New York, N.Y.: Published by R. Cronau, 340 East 198th Street, New York, pages 84–85

As Edwin Clark [...] wrote in 1850: "[...] The lofty towers of the castle overhang the western approach to the Bridge, and the line passes into Conway through an opening pierced in the embattled wall, which entirely surrounds the town. These fortifications are in good preservation, and rank among the most perfect examples of the strongholds of the 13th century."

2022 January 12, Dr. Joseph Brennan, “Castles: ruined and redeemed by rail”, in RAIL, number 948, page 54

With the numerous soldiers of Asia, with all of their warlike stores, ships, and military engines, that wealth and power could command, the Turks at once resolved to crush an enemy which, creeping on by degrees, had from their strong-hold in the Morea acquired Thrace and Macedonia, and had led their armies even to the gates of Constantinople, while their extensive commercial relations gave every European nation an interest in their success.

1826, [Mary Shelley], chapter X, in The Last Man. [...] In Three Volumes, volume I, Paris: Published by A. and W[illiam] Galignani, at the French, English, Italian, German, and Spanish Library, No. 18, rue Vivienne, page 228

The Lord Mayor, in the stronghold of the mighty Mansion House, gave orders to his fifty cooks and butlers to keep Christmas as a Lord Mayor's household should; and even the little tailor, whom he had fined five shillings on the previous Monday for being drunk and blood-thirsty in the streets, stirred up to-morrow's pudding in his garret, while his lean wife and the baby sallied out to buy the beef.

1843 December 19, Charles Dickens, “Stave I. Marley’s Ghost.”, in A Christmas Carol. In Prose. Being a Ghost Story of Christmas, London: Chapman & Hall, […], page 16

Bridge End is the border station and the scene of many a sad parting between enterprising shoppers and their purchases—for it is a stronghold of the Customs !—and half an hour is allowed in the timetable for examination and shunting.

1949 November and December, K. Longbottom, “By Goods Train to Gweedore”, in Railway Magazine, page 353

Thailand has been broadly split along north-south political lines since Thaksin [Shinawatra]'s ouster. A bastion of the conservative, pro-establishment Democrat Party, southern Thailand historically hosts much of the country's wealth and tourism. The poorer, agrarian north and northeast, where Thaksin's populist policies won him legions of supporters, remain Shinawatra strongholds.

2015 May 10, Amy Sawitta Lefevre, “Thai King Leaves Hospital after Seven Months, Returns to Seaside Palace”, in Reuters‎, archived from the original on 28 December 2017

It's in this horse-opera mode that War For The Planet Of The Apes finds its most rewarding rhythms: in the parallels between Caesar's woodland stronghold and the archetypal frontier settlements of Western fiction; […]

2017 July 7, Ignatiy Vishnevetsky, “The Ambitious War For The Planet Of The Apes Ends Up Surrendering to Formula”, in The A.V. Club‎, archived from the original on 27 November 2017