In the Bing search context, cvid represents the JavaScript parameter ConversationId. Bing uses this key to identify your search result collection as its reply to your query, q. Similarly, pq is PartialQuery. These and other parameters may also apply to different kinds of searches, such as image or video searches.
Next, qs is your query's SuggestionType, sc shows your SuggestionCount, and from the suggestion list (dropped down, if enabled), sp shows the SuggestionPosition you chose. In your case, you did not select a suggestion, so &sp=-1. Toward the end of your string, sk is the SkipValue, because you might skip through your result pages, first tells the issuer how many results belong on the first page, and I'll let you figure out what FORM means. ;)
TRY:
Navigate to Bing, conduct a search, choose some options, change your displays, and change some search types. Next, open file explorer and navigate to your Windows OS equivalent of the following path.
C:\Users\{user}\AppData\Local\Microsoft\Windows
Next, you may need to adjust your View temporarily to "Show hidden files, folders, and drives." View tab > Options > Change... > View tab again, and click the bullet to "Show...".
In File Explorer's Search pane at the upper right, enter *.js to find all JavaScript files. It may point you several subfolders deeper, and the folder names may be hashed. Choose a JavaScript file you find interesting, right-click the file, and open it with Notepad, your favorite IDE, or some similar editor. You should see something akin to this (truncated; may not run independently):
var AutoSuggest,__extends,Bing,sa_inst;(function(n){var t;(function(n){var t,i,r,u,f,e;(function(n){n.User="SRCHHPGUSR"})(t=n.CookieNames||(n.CookieNames={})),function(n){n.AutoSuggest="AS"}(i=n.CrumbNames||(n.CrumbNames={})),function(n){n.CursorPosition="cp";n.ConversationId="cvid";n.SuggestionCount="sc";n.PartialQuery="pq";n.SuggestionPosition="sp";n.SuggestionType="qs";n.PreviewPaneSuggestionType="qsc";n.SkipValue="sk";n.PreviewPaneSkipValue="skc";n.Ghosting="ghc";n.Css="css";n.Count="count";n.DataSet="ds";n.SessionId="sid";n.TimeStamp="qt";n.Query="q";n.ImpressionGuid="ig";n.QFQuery="qry";n.BaseQuery="bq";n.FormCode="form";n.HashedMuid="nclid";n.RequestElToken="elvr";n.ElTokenValue="elv";n.AppId="appid";n.History="history";n.NoHistory="nohs";n.ApiTextDecoration="textdecorations";n.ClientId="clientid";n.Market="mkt";n.Scope="scope";n.CountryCode="cc";n.HomeGeographicRegion="hgr";n.SetLang="setlang";n.ZeroInputSerp="zis"}(r=n.QueryParams||(n.QueryParams={}))
I hope that helps someone! :D
