Firewalls are important for keeping systems secure from outside threats, but there are other ways to refer to this technology. One synonym is a network security device, which typically includes a combination of hardware and software. Another term is a packet filter, which can be used to inspect network traffic and block potentially malicious packets. A third option is a perimeter security system, which encompasses a range of security measures used to protect against external threats. Lastly, some may simply refer to firewalls as security gates, as they act as a gatekeeper to entry into a network or device. No matter the term used, firewalls remain an important part of cybersecurity.