Language shapes how we word, think, collaborate, and build in the technology realm. For decades, the tech industry has relied on terminology that, while once widely accepted, carries historical and cultural baggage. Today, there’s a growing movement to adopt language that is both more inclusive and more precise.
Two of the biggest shifts you’re likely to see across documentation, codebases, and security practices are the following.
- Moving from Master/Slave → Primary/Secondary (or Leader/Follower)
- Moving from Whitelist/Blacklist → Allowlist/Blocklist
Let’s explore why these changes matter and what they mean for the future of technology.
A Personal Reflection on Language Evolution
What sparked this blog was remembering back when the US moved from saying “mailman” to “letter carrier.” At that time in the early 1990s, it felt like a small, almost trivial shift, but it stuck with me. That change made it clear that language doesn’t just describe roles; it shapes who feels included or excluded within the spoken words. This switch was one of those quiet moments that helped to open my eyes to how many everyday terms carry assumptions we rarely question.
Looking back, that’s when I started to realize that similar updates, like the ones we’re seeing in technology today, aren’t just about words. They’re about making space for everyone and thusly I am scribing this post to share.
The Problem with Legacy Terminology
1. Historical weight and unintended harm
Terms like “master” and “slave” are deeply rooted in historical systems of oppression. In computing, they were used to describe control relationships (e.g., one system directs another), but the metaphor itself reflects ownership and subjugation. [inclusivenaming.org]
Similarly, “blacklist” and “whitelist” reinforce a problematic association where “black” implies bad and “white” implies good which is an analogy that can perpetuate unconscious bias, even if unintentionally. [splunk.com]
Even when these terms are used purely in technical contexts, they don’t exist in a vacuum. Language carries meaning beyond its immediate definition.
2. It’s not just about sensitivity, it’s about clarity
Interestingly, these legacy terms are not only problematic but they are often less clear by definition.
For example:
- “Whitelist” doesn’t inherently explain what happens when it is used
- It makes one think… “Are we talking a list of paint colors here people?”
- “Allowlist” immediately communicates what is allowed
- “Blocklist” directly describes what is blocked [linkedin.com]
The newer alternatives are function-based, making systems easier to understand, especially for non-experts or cross-functional teams.
The Modern Alternatives
Master/Slave → Primary/Secondary (or Leader/Follower)
Instead of describing systems in terms of control and subjugation, modern terminology focuses on functionality:
- Primary: The main source or controlling system
- Secondary / Replica: Supporting or synchronized systems
This shift removes harmful connotations while improving accuracy. In many systems, the “primary” node simply serves as the main data source with no metaphor required.
Many organizations and frameworks have already adopted alternatives like:
- Primary / Replica
- Leader / Follower
- Main / Backup [linuxreviews.org]
Whitelist/Blacklist → Allowlist/Blocklist
In cybersecurity and access control:
- Allowlist: A list of entities explicitly permitted
- Blocklist: A list of entities explicitly denied [cube.exchange]
Beyond inclusivity, these terms are:
- Easier to understand
- More globally neutral
- Better aligned with how systems actually behave
For example, an allowlist reflects a deny-by-default approach, where only approved items are permitted which makes the system more predictable and secure. [cube.exchange]
Why the Industry Is Changing Now
1. A push for inclusive culture
The tech industry has long faced challenges around diversity and inclusion. Language may seem like a small piece of the puzzle, but it plays a powerful role in shaping culture and belonging. [bizstream.com]
By adopting inclusive terms, organizations signal that they are actively working to create a space where everyone feels welcome.
2. Industry-wide momentum
Major organizations, including open-source communities, cloud providers, and software companies, have already begun transitioning away from outdated terminology. [businessinsider.com]
This momentum matters as documentation, tools, and platforms evolve; new terminology becomes the standard for the next generation of developers.
3. Better communication across global teams
Modern software is built by distributed, international teams with diversity at the core. Terms that rely on cultural assumptions (like associations mentioned above) don’t always translate well.
Function-based language like allow, block, primary, and secondary is all of the following.
- Easier to translate
- Easier to teach
- Easier to adopt universally
Addressing Common Concerns
“Isn’t this just changing words?”
That’s the questions I used to ask myself, and I imagine most would think it is a fair question. After investigating, this shift is about more than semantics.
- Clarity improves documentation
- Inclusivity improves collaboration
- Precision improves system design
Language evolves naturally in technology. Just as we moved from “webmaster” to “site owner,” or from “mainframe operator” to “cloud engineer,” this is simply the next step.
“What about legacy systems?”
Not everything can possibly change overnight as many teams take a pragmatic approach to assignments and work.
- They may use modern terminology in new code and documentation
- They can maintain legacy terms when required for compatibility
- They gradually refactor where possible
The goal is progress towards perfection, not instant perfection because things may change again.
Practical Steps to Start the Transition
If you’re writing code, documentation, or internal policies, here are some easy ways to begin:
- Replace “
master” with primary (or main) - Replace “
slave” with secondary or replica - Replace “
whitelist” with allowlist - Replace “
blacklist” with blocklist
Update style guides and coding standards and encourage consistency across teams.
Final Thoughts
The shift from master/slave to primary/secondary, and from whitelist/blacklist to allowlist/blocklist, reflects something bigger than a naming update, it reflects a maturing industry and its language.
An industry that:
- Values clarity over tradition
- Prioritizes inclusion alongside innovation
- Recognizes that even small changes can have meaningful impact
In the end, better language doesn’t just make better code, it helps build a more friendly and collaborative future for everyone in tech.