Index: wp-admin/async-upload.php
===================================================================
--- wp-admin/async-upload.php	(revision 19592)
+++ wp-admin/async-upload.php	(working copy)
@@ -52,7 +52,7 @@
 $id = media_handle_upload('async-upload', $_REQUEST['post_id']);
 if ( is_wp_error($id) ) {
 	echo '<div class="error-div">
-	<a class="dismiss" href="#" onclick="jQuery(this).parents(\'div.media-item\').slideUp(200, function(){jQuery(this).remove();});">' . __('Dismiss') . '</a>
+	<a class="dismiss" href="#" onclick="jQuery(this).parents(\'div.media-item\').slideUp(200, function(){jQuery(this).remove();});">' . _x( 'Dismiss', 'Cancel upload' ) . '</a>
 	<strong>' . sprintf(__('&#8220;%s&#8221; has failed to upload due to an error'), esc_html($_FILES['async-upload']['name']) ) . '</strong><br />' .
 	esc_html($id->get_error_message()) . '</div>';
 	exit;
Index: wp-admin/includes/dashboard.php
===================================================================
--- wp-admin/includes/dashboard.php	(revision 19592)
+++ wp-admin/includes/dashboard.php	(working copy)
@@ -1194,7 +1194,7 @@
 		}
 		$notice .= "<p class='browser-update-nag{$browser_nag_class}'>{$msg}</p>";
 		$notice .= '<p>' . sprintf( __( '<a href="%1$s" class="update-browser-link">Update %2$s</a> or learn how to <a href="%3$s" class="browse-happy-link">browse happy</a>' ), esc_attr( $response['update_url'] ), esc_html( $response['name'] ), 'http://browsehappy.com/' ) . '</p>';
-		$notice .= '<p class="hide-if-no-js"><a href="" class="dismiss">' . __( 'Dismiss' ) . '</a></p>';
+		$notice .= '<p class="hide-if-no-js"><a href="" class="dismiss">' . _x( 'Dismiss', 'Close info window' ) . '</a></p>';
 		$notice .= '<div class="clear"></div>';
 	}
 
@@ -1286,7 +1286,7 @@
 	?>
 	<div id="welcome-panel" class="<?php echo esc_attr( $classes ); ?>">
 	<?php wp_nonce_field( 'welcome-panel-nonce', 'welcomepanelnonce', false ); ?>
-	<a class="welcome-panel-close" href="<?php echo esc_url( admin_url( '?welcome=0' ) ); ?>"><?php _e('Dismiss'); ?></a>
+	<a class="welcome-panel-close" href="<?php echo esc_url( admin_url( '?welcome=0' ) ); ?>"><?php _ex( 'Dismiss', 'Close info window' ); ?></a>
 	<div class="wp-badge"><?php printf( __( 'Version %s' ), $display_version ); ?></div>
 
 	<div class="welcome-panel-content">
Index: wp-includes/script-loader.php
===================================================================
--- wp-includes/script-loader.php	(revision 19592)
+++ wp-includes/script-loader.php	(working copy)
@@ -98,7 +98,7 @@
 
 	$scripts->add( 'wp-pointer', "/wp-includes/js/wp-pointer$suffix.js", array( 'jquery-ui-widget', 'jquery-ui-position' ), '20111129a', 1 );
 	$scripts->localize( 'wp-pointer', 'wpPointerL10n', array(
-		'dismiss' => __('Dismiss'),
+		'dismiss' => _x( 'Dismiss', 'Close info window' ),
 	) );
 
 	$scripts->add( 'autosave', "/wp-includes/js/autosave$suffix.js", array('schedule', 'wp-ajax-response'), '20111129', 1 );
@@ -207,7 +207,7 @@
 		'security_error' => __('Security error.'),
 		'file_cancelled' => __('File canceled.'),
 		'upload_stopped' => __('Upload stopped.'),
-		'dismiss' => __('Dismiss'),
+		'dismiss' => _x( 'Dismiss', 'Cancel upload' ),
 		'crunching' => __('Crunching&hellip;'),
 		'deleted' => __('moved to the trash.'),
 		'error_uploading' => __('&#8220;%s&#8221; has failed to upload.')