Why Is Merriam-Webster Website So Slow? Here Are The Reasons

Merriam-Webster is the oldest dictionary publisher in the United States. According to their website, the desktop website receives over 32 million unique visitors each year, with an additional 18.5 million coming from mobile phones. The app contributes to around 9 million unique a year.

A speed report from Lighthouse paints a rather grim picture and scores Merriam-Webster’s website 15 seconds on the speed index (SI), and 31 on Performance.

There are many reasons why the Merriam-Webster website is so slow. This includes:

• Bloated JavaScript files
• Unused CSS files
• Unnecessarily large image files
• Old Image formats
• Large DOM size
• Duplicate JavaScript modules

Let’s look at each of these reasons and identify potential ways that Merriam-Webster can make its website load faster.

But before we do that, a quick word about our website CWVIQ.com - we are a free email alert service that sends out notification any time your website is loading very slowly (often due to heavy traffic, or poor scripts). If you have a website, consider setting up an alert so that you can fix issues before they become major. 

Bloated JavaScript files

Merriam-Webster uses a lot of JavaScript to run the website. However, loading them all from one source could slow up the performance of the website. Merriam-Webster can avoid this by splitting the code into smaller files. This way, you only load files that are necessary.

The Merriam-Webster website can be as much as 6.07 seconds faster by adopting this technique.

Unused CSS files

Merriam-Webster uses CSS files to load the styling elements for the website. However, this file contains a lot of unused scripts that can be slowing down page loading by as much as 0.33 seconds. Code splitting may help avoid this issue.

Unnecessarily large image files

Another common problem that users face – especially when they access the website while on the move – is having to load unnecessarily large image files that are not optimized for the mobile phone. Not everyone has access to WiFi at all times. Loading oversized product images is unnecessary.

According to the Lighthouse estimate, Merriam Webster website homepage can load 0.21 seconds faster if it made all the images more cellular-data-friendly.

Old Image formats

The Merriam-Webster website uses a lot of JPG and PNG files that are considered outdated and heavy for modern web use. Replacing them with WebP and AVIF files can save as much as 3.44 seconds from the page loading time.

Large DOM size

The Merriam-Webster website takes close to 31.7 seconds to evaluate all the scripts, parse them, compile, and render them. This can be minimized by minimizing the main-thread work.

They may also look at reducing the number of nodes in the DOM. In simpler terms, you need to make sure that the main HTML code is smaller and has fewer nodes. I have explained this in greater detail in this article about DOMContentLoaded.

Duplicate JavaScript Modules

Merriam-Webster has a number of JavaScript modules that are duplicated within the code. This means that the browser has to read through and parse each of these codes multiple times, thereby expending unnecessary resources. According to the Speed report analysis we did, Merriam-Webster sees an additional delay of 3.25 seconds due to this issue.