“The Latin osculum is neither very old nor frequent. It is one of three words that can be translated by the English, "kiss."”

The Cultivation of Conspiracy (1998)
Context: The Latin osculum is neither very old nor frequent. It is one of three words that can be translated by the English, "kiss." In comparison with the affectionate basium and the lascivious suavium, osculum was a latecomer into classical Latin, and was used in only one circumstance as a ritual gesture: In the second century, it became the sign given by a departing soldier to a woman, thereby recognizing her expected child as his offspring.
In the Christian liturgy of the first century, the osculum assumed a new function. It became one of two high points in the celebration of the Eucharist. Conspiratio, the mount-to-mouth kiss, became the solemn liturgical gesture by which participants in the cult-action shared their breath or spirit with one another. It came to signify their union in one Holy Spirit, the community that takes shape in God's breath. The ecclesia came to be through a public ritual action, the liturgy, and the soul of this liturgy was the conspiratio. Explicitly, corporeally, the central Christian celebration was understood as a co-breathing, a con-spiracy, the bringing about of a common atmosphere, a divine milieu.