diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index a191f50da7..b8ddb0cf76 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -79,7 +79,7 @@
bulk deletes by `delete_all`.
Supports skipping or upserting duplicates through the `ON CONFLICT` syntax
- for Postgres (9.5+) and Sqlite (3.24+) and `ON DUPLICATE KEY UPDATE` syntax
+ for PostgreSQL (9.5+) and SQLite (3.24+) and `ON DUPLICATE KEY UPDATE` syntax
for MySQL.
*Bob Lail*
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 6981ea6ecd..9f0335b31d 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -966,7 +966,7 @@ module ActiveRecord
# [:on_update]
# Action that happens ON UPDATE. Valid values are +:nullify+, +:cascade+ and +:restrict+
# [:validate]
- # (Postgres only) Specify whether or not the constraint should be validated. Defaults to +true+.
+ # (PostgreSQL only) Specify whether or not the constraint should be validated. Defaults to +true+.
def add_foreign_key(from_table, to_table, options = {})
return unless supports_foreign_keys?
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index fa6f0d36ec..67a63cd2d1 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -180,7 +180,7 @@ module ActiveRecord
# raw_timestamp_to_cache_version(timestamp)
# # => "20181015200215266505"
#
- # Postgres truncates trailing zeros,
+ # PostgreSQL truncates trailing zeros,
# https://github.com/postgres/postgres/commit/3e1beda2cde3495f41290e1ece5d544525810214
# to account for this we pad the output with zeros
def raw_timestamp_to_cache_version(timestamp)
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 4ef0c1b6a6..a87b9e7db2 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -85,14 +85,14 @@ module ActiveRecord
# ==== Options
#
# [:returning]
- # (Postgres-only) An array of attributes to return for all successfully
+ # (PostgreSQL only) An array of attributes to return for all successfully
# inserted records, which by default is the primary key.
# Pass returning: %w[ id name ] for both id and name
# or returning: false to omit the underlying RETURNING SQL
# clause entirely.
#
# [:unique_by]
- # (Postgres and SQLite only) By default rows are considered to be unique
+ # (PostgreSQL and SQLite only) By default rows are considered to be unique
# by every unique index on the table. Any duplicate rows are skipped.
#
# To skip rows according to just one unique index pass :unique_by.
@@ -154,7 +154,7 @@ module ActiveRecord
# ==== Options
#
# [:returning]
- # (Postgres-only) An array of attributes to return for all successfully
+ # (PostgreSQL only) An array of attributes to return for all successfully
# inserted records, which by default is the primary key.
# Pass returning: %w[ id name ] for both id and name
# or returning: false to omit the underlying RETURNING SQL
@@ -202,14 +202,14 @@ module ActiveRecord
# ==== Options
#
# [:returning]
- # (Postgres-only) An array of attributes to return for all successfully
+ # (PostgreSQL only) An array of attributes to return for all successfully
# inserted records, which by default is the primary key.
# Pass returning: %w[ id name ] for both id and name
# or returning: false to omit the underlying RETURNING SQL
# clause entirely.
#
# [:unique_by]
- # (Postgres and SQLite only) By default rows are considered to be unique
+ # (PostgreSQL and SQLite only) By default rows are considered to be unique
# by every unique index on the table. Any duplicate rows are skipped.
#
# To skip rows according to just one unique index pass :unique_by.
diff --git a/activerecord/test/cases/adapters/mysql2/schema_test.rb b/activerecord/test/cases/adapters/mysql2/schema_test.rb
index 1283b0642c..b8f51acba0 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_test.rb
@@ -41,7 +41,7 @@ module ActiveRecord
column_24 = @connection.columns(:mysql_doubles).find { |c| c.name == "float_24" }
column_25 = @connection.columns(:mysql_doubles).find { |c| c.name == "float_25" }
- # Mysql floats are precision 0..24, Mysql doubles are precision 25..53
+ # MySQL floats are precision 0..24, MySQL doubles are precision 25..53
assert_equal 24, column_no_limit.limit
assert_equal 24, column_short.limit
assert_equal 53, column_long.limit
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md
index 7f17b19a13..d765e32ac7 100644
--- a/guides/source/active_record_basics.md
+++ b/guides/source/active_record_basics.md
@@ -105,7 +105,7 @@ depending on the purpose of these columns.
fields that Active Record will look for when you create associations between
your models.
* **Primary keys** - By default, Active Record will use an integer column named
- `id` as the table's primary key (`bigint` for Postgres and MYSQL, `integer`
+ `id` as the table's primary key (`bigint` for PostgreSQL and MySQL, `integer`
for SQLite). When using [Active Record Migrations](active_record_migrations.html)
to create your tables, this column will be automatically created.
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index dab73bfbc2..d6fccadb28 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -1206,7 +1206,7 @@ The I18n API described in this guide is primarily intended for translating inter
Several gems can help with this:
* [Globalize](https://github.com/globalize/globalize): Store translations on separate translation tables, one for each translated model
-* [Mobility](https://github.com/shioyama/mobility): Provides support for storing translations in many formats, including translation tables, json columns (Postgres), etc.
+* [Mobility](https://github.com/shioyama/mobility): Provides support for storing translations in many formats, including translation tables, json columns (PostgreSQL), etc.
* [Traco](https://github.com/barsoom/traco): Translatable columns for Rails 3 and 4, stored in the model table itself
Conclusion