diff --git a/mod/message.php b/mod/message.php
index 99fb6b3b4..928f575ef 100644
--- a/mod/message.php
+++ b/mod/message.php
@@ -436,7 +436,7 @@ function render_messages(array $msg, string $t): string
 		$to_name_e = $rr['name'];
 
 		if (is_null($rr['url'])) {
-			// contact-id is pointing to a non existing contact
+			// contact-id is pointing to a nonexistent contact
 			continue;
 		}
 
diff --git a/src/Network/Probe.php b/src/Network/Probe.php
index 88c256fe0..02498827e 100644
--- a/src/Network/Probe.php
+++ b/src/Network/Probe.php
@@ -2280,7 +2280,7 @@ class Probe
 				]
 			];
 		} catch (Exception $e) {
-			// Default values for non existing targets
+			// Default values for nonexistent targets
 			$data = [
 				'name' => $url, 'nick' => $url, 'url' => $url, 'network' => Protocol::PHANTOM,
 				'photo' => DI::baseUrl() . Contact::DEFAULT_AVATAR_PHOTO
diff --git a/src/Protocol/ActivityPub/Queue.php b/src/Protocol/ActivityPub/Queue.php
index 9180de08f..d77785fe6 100644
--- a/src/Protocol/ActivityPub/Queue.php
+++ b/src/Protocol/ActivityPub/Queue.php
@@ -252,7 +252,7 @@ class Queue
 	{
 		$entries = DBA::select('inbox-entry', ['id', 'type', 'object-type', 'object-id', 'in-reply-to-id'], ["`trust` AND `wid` IS NULL"], ['order' => ['id' => true]]);
 		while ($entry = DBA::fetch($entries)) {
-			// Don't process entries of items that are answer to non existing posts
+			// Don't process entries of items that are answer to nonexistent posts
 			if (!empty($entry['in-reply-to-id']) && !Post::exists(['uri' => $entry['in-reply-to-id']])) {
 				continue;
 			}
diff --git a/src/Util/PidFile.php b/src/Util/PidFile.php
index 649a15679..1d9019d73 100644
--- a/src/Util/PidFile.php
+++ b/src/Util/PidFile.php
@@ -31,7 +31,7 @@ class PidFile
 	 *
 	 * @param string $file Filename of pid file
 	 *
-	 * @return boolean|string PID or "false" if not existent
+	 * @return boolean|string PID or "false" if nonexistent
 	 */
 	private static function pidFromFile(string $file)
 	{
diff --git a/tests/src/Core/Config/ConfigTest.php b/tests/src/Core/Config/ConfigTest.php
index cf13ea05a..b526fc13b 100644
--- a/tests/src/Core/Config/ConfigTest.php
+++ b/tests/src/Core/Config/ConfigTest.php
@@ -346,7 +346,7 @@ class ConfigTest extends DatabaseTest
 		// without refresh
 		self::assertNull($this->testedConfig->get('test', 'it'));
 
-		/// beware that the cache returns '!<unset>!' and not null for a non existing value
+		/// beware that the cache returns '!<unset>!' and not null for a nonexistent value
 		self::assertNull($this->testedConfig->getCache()->get('test', 'it'));
 
 		// with default value
diff --git a/tests/src/Core/PConfig/PConfigTest.php b/tests/src/Core/PConfig/PConfigTest.php
index 2aade836d..784f81b2e 100644
--- a/tests/src/Core/PConfig/PConfigTest.php
+++ b/tests/src/Core/PConfig/PConfigTest.php
@@ -324,7 +324,7 @@ abstract class PConfigTest extends MockedTest
 		// without refresh
 		self::assertNull($this->testedConfig->get(0, 'test', 'it'));
 
-		/// beware that the cache returns '!<unset>!' and not null for a non existing value
+		/// beware that the cache returns '!<unset>!' and not null for a nonexistent value
 		self::assertNull($this->testedConfig->getCache()->get(0, 'test', 'it'));
 
 		// with default value