En masse

[L]et the clergy, en Maſſe, preach him down, admoniſh their ſeveral congregations to be attentive to the duty they owe to the beſt of kings and to their country, and to ſeek to deprecate, by the holineſs of their lives, the wrath of the Almighty.

Source: wiktionary

In the case of the very large caps called detonators, which are used in firing dynamite and gun cotton, is there not some risk of explosion en masse?—Yes, if you get large quantities of percussion powder together, there would be greater danger; […]

Source: wiktionary

He [Goh Siew Tin] had traded largely with Java, and on the day of his funeral all the Chinese shops trading in Java produce were closed, while the pupils of the Toh Lam (Hokien) Mandarin School (of which Mr. Goh Siew Tin was President) en masse attended the funeral.

Source: wiktionary

During inclement weather it is necessary for this group to meet in one gymnasium. Therefore it was decided to consider the whole group as one class. Two instructors are assigned to each class. Part of the work is given en masse, and for the remainder the class is divided between the two instructors.

Source: wiktionary