diff --git a/wp-admin/includes/screen.php b/wp-admin/includes/screen.php
index 9ddf1a6e7c..aa19f46f77 100644
--- a/wp-admin/includes/screen.php
+++ b/wp-admin/includes/screen.php
@@ -565,7 +565,8 @@ final class WP_Screen {
 	 *
 	 * @since 3.3.0
 	 *
-	 * @param string
+	 * @param string $option Option ID.
+	 * @param mixed $key Optional. Specific array key for when the option is an array.
 	 */
 	public function get_option( $option, $key = false ) {
 		if ( ! isset( $this->_options[ $option ] ) )
diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 4a70a2422a..557d2c1781 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -227,7 +227,7 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
  * @since 1.2.0
  *
  * @param int|string|array $category Category ID, name or slug, or array of said.
- * @param int|object $_post Optional. Post to check instead of the current post. (since 2.7.0)
+ * @param int|object $post Optional. Post to check instead of the current post. (since 2.7.0)
  * @return bool True if the current post is in any of the given categories.
  */
 function in_category( $category, $post = null ) {
@@ -1050,6 +1050,7 @@ function tag_description( $tag = 0 ) {
  * @since 2.8
  *
  * @param int $term Optional. Term ID. Will use global term ID by default.
+ * @param string $taxonomy Optional taxonomy name. Defaults to 'post_tag'.
  * @return string Term description, available.
  */
 function term_description( $term = 0, $taxonomy = 'post_tag' ) {
@@ -1156,7 +1157,7 @@ function the_terms( $id = 0, $taxonomy, $before = '', $sep = ', ', $after = '' )
  *
  * @since 3.1.0
  *
- * @param string|int|array $tag Optional. The category name/term_id/slug or array of them to check for.
+ * @param string|int|array $category Optional. The category name/term_id/slug or array of them to check for.
  * @param int|object $post Optional. Post to check instead of the current post.
  * @return bool True if the current post has any of the given categories (or any category, if no category specified).
  */
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 606557670c..6e53d33af0 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -2887,6 +2887,7 @@ function wp_set_post_tags( $post_id = 0, $tags = '', $append = false ) {
  *
  * @param int $post_id Post ID.
  * @param string $tags The tags to set for the post, separated by commas.
+ * @param string $taxonomy Taxonomy name. Defaults to 'post_tag'.
  * @param bool $append If true, don't delete existing tags, just add on. If false, replace the tags with the new tags.
  * @return mixed Array of affected term IDs. WP_Error or false on failure.
  */
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 1c3704e30c..626292cb04 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -164,11 +164,12 @@ function count_user_posts($userid) {
  * Number of posts written by a list of users.
  *
  * @since 3.0.0
- * @param array $user_ids Array of user IDs.
+ *
+ * @param array $users Array of user IDs.
  * @param string|array $post_type Optional. Post type to check. Defaults to post.
  * @return array Amount of posts each user has written.
  */
-function count_many_users_posts($users, $post_type = 'post' ) {
+function count_many_users_posts( $users, $post_type = 'post' ) {
 	global $wpdb;
 
 	$count = array();
diff --git a/wp-login.php b/wp-login.php
index ca647652ca..a67d2c510e 100644
--- a/wp-login.php
+++ b/wp-login.php
@@ -239,8 +239,7 @@ function retrieve_password() {
  *
  * @param string $key Hash to validate sending user's password
  * @param string $login The user login
- *
- * @return object|WP_Error
+ * @return object|WP_Error User's database row on success, error object for invalid keys
  */
 function check_password_reset_key($key, $login) {
 	global $wpdb;
@@ -264,9 +263,8 @@ function check_password_reset_key($key, $login) {
 /**
  * Handles resetting the user's password.
  *
- * @uses $wpdb WordPress Database object
- *
- * @param string $key Hash to validate sending user's password
+ * @param object $user The user
+ * @param string $new_pass New password for the user in plaintext
  */
 function reset_password($user, $new_pass) {
 	do_action('password_reset', $user, $new_pass);