Here’s a list of macOS system processes.

Process Description
activitymonitord Gathers system statistics for Activity Monitor. Located inside the Activity Monitor application bundle.
Airport Base Station Agent Used when your network has an Airport base station. It will notify you when there are problems.
aosnotifyd Apple Online Services (AOS) notification daemon for notifications from sync services, e.g., MobileMe notifications
AppleSpell.service Checks the spelling of what you type
autofsd Automatically mounts (connects to) file systems. Used to automatically connect to file systems on the network when the network changes.
backupd Time Machine backup daemon.
bash BASH is a command shell that comes with macOS. It powers the command-line (Terminal) and runs scripts. There are other variants like bash and zsh.
blued Bluetooth monitor. Handles Bluetooth connection requests and other Bluetooth functions.
configd Maintains system configuration information. Notifies applications when configurations change.
coreaudiod Used by Core Audio to manage audio devices.
coreservicesd  
cron Runs various programs and scheduled times. Cron is used mainly to support regular system maintenance scripts.
cupsd “Common UNIX Printing System” print support daemon. Handles print queues and requests.
cvmsServ Part of the OpenGL (graphics) system. Possibly related to OpenCL.
DashboardClient Dashboard helper. Used by the Dashboard to support widgets.
DirectoryService Handles access to defined directories, LDAP, ActiveDirectory, Bonjour, etc. Also tracks information about file servers, printers, etc.
diskarbitrationd Watches for file system mounts and handles who gets to access them.
diskimages-helper Used when mounting and accessing disk images.
distnoted Distributed notification server.
dynamic_pager macOS swap memory manager. Handles swapping memory to disk.
eapolclient Extensible Authentication Protocol (EAP) client. Used when your wireless network uses 802.1x/EAP-FAST authentication.
fontd macOS font daemon. Makes fonts available to the system.
fontworker macOS font registration daemon. Registers and validates fonts.
fseventsd Responsible for tracking file system events, e.g., file creation, file deletion. Those events are broadcast to Mac applications so they can react when files are changed while they are running.
hidd Human Interface Device Daemon. Manages input devices like keyboards and mice.
httpd The Apache web server. Serves up web page requests. This is active when you turn on the personal web server.
kernel_task macOS memory manager. Allocates memory from the operating system.
KernelEventAgent Responsible for displaying disk full and unresponsive file server messages
kextd macOS kernel extension daemon. Handles the loading and unloading of kernel extensions (drivers).
krb5kdc Kerberos 5 Key Distribution Center. Responsible for shared/distributed logins between computers.
launchd macOS process launcher. Responsible for starting up system processes and keeping them running.
LKDCHelper Assists with Kerberos (single-sign-on)
login Logs a user into the computer
loginwindow User login session
mDNSResponder Bonjour daemon. Responsible for handling bonjour network broadcasts.
mds Metadata Server. Responsible for indexing files for Spotlight.
mdworker Created by the Metadata server when it indexes files.
mdworker32 Created by the Metadata server when it indexes files.
mobilemesyncclient Synchronization with MobileMe.
nmbd NetBIOS name server. Interfaces with Windows networks.
notifyd Notification service used by the notify command.
ocspd Online Certificate Status Protocol daemon. Used by the security framework during certificate verification.
pboard Pasteboard. Handles copy and paste.
Quick Look Helper Started by Quicklook.
quicklookd32 Started by Quicklook.
securityd Security context daemon. Handles access to keychain items.
sh SH is a command shell that comes with macOS. It powers the command-line (Terminal) and runs scripts. There are other variants like bash and zsh.
SubmitDiagInfo Periodically sends diagnostic information to Apple. Only runs if the user has “opted-in” to send information.
syslogd System logging daemon. Accepts system log messages and outputs them to the log.
SystemStarter Old method for starting and stopping system services. Replaced by launchd. Starts up startup items.
SystemUIServer Responsible for some of the macOS user interface such as the right hand side of the menu (clock, power, etc.).
usbmuxd Part of the mobile device framework
UserEventAgent Loads system plugins to handle high-level events.
WindowServer Part of the graphics system.
zsh ZSH is a command shell that comes with macOS. It powers the command-line (Terminal) and runs scripts. There are other variants like bash and zsh.