systemd

linux

Init system and service manager for Linux, responsible for bootstrapping user space and managing system processes

Pronunciation

Correct

SIS-tem-dee

/ˈsɪstəmˌdiː/

The 'd' suffix is a Unix convention for daemon. Pronounced as 'system' + the letter 'D'. Confirmed by creator Lennart Poettering.

Source: systemd.io(official docs)