Definition of "roundhead"

The roundhead screw and its fraternal twins, the button head and pan head screws, have a head that is flat on the bottom and hemispherical on top.

2000, Reed Karen, The Complete Idiot's Guide to Woodworking, page 182

You can use flat-head screws and plug the holes, or you can use roundhead blue screws and let the heads project.

2010, H. H. Windsor, Mission Furniture: How to Make It, page 58

You roundhead whore, sock it up, or me will kill you, begar.

1672, John Lacy, The Old Troop: Or, Monsieur Raggou. As it was Acted at the Theatre Royal, page 11

Colonel Middleton was dismounted amongst the king's forces, of whom one, taking him for a commander of their's, mounted him again, and bid him make haste, and kill a roundhead ; and so he escaped.

1840, Daniel Defoe, Memoirs of a Cavalier, page 331

The parliament, which either could not or would not be prorogued till the end of October, busied itself exceedingly regarding the queen's residence with her children, and testified the utmost jealousy of her confessor, father Phillipss, who underwent several examinations; and may portentous hints were dropped by the roundhead orators in the house of commons respecting the queen's establishment of Capuchins at Somerset-house.

2010, Agnes Strickland, Elizabeth Strickland, Lives of the Queens of England from the Norman Conquest, pages 276–277

He added that they 'fell upon all that have short hair' and cried out, 'A roundhead! A roundhead!'

2014, Peter Ackroyd, Civil War: The History of England

The roundheads in the school showers easily equalled the cavaliers.

1992, John Hoyland, Fathers and Sons, page 94

Since penile preference is so tied up with personal aesthetics and body image, it seems both logical and fair to leave the choice of cavalier or roundhead to the owner of the organ, thus avoiding the sort of life-long pain expressed in a comment like this: […]

2008, “Objections of a sentimental character: The subjective dimension of foreskin loss”, in Matatu, number 37, page 158

I knew about the English Civil War, Cavaliers (wrong but romantic) versus Roundheads (right but repulsive), but I didn't think that was what he was talking about. I shook my head. “It means our willies aren't circumcised,” he explained. “Are you a cavalier or a roundhead?”

2013, Ellen Datlow, Hauntings, page 155

The top of the caisson will be at the same level as the bag-work foundation of the pier, and a roundhead, composed of 45-ton granite faced concrete blocks, will be built on it.

1899, Junior Institution of Engineers (London, England), Journal and Record of Transactions: 1899-1900 - Volume 10, page 251

The smallness of the damage done at Purfleet is remarkable, when it is remembered that the impact of a large steamship is sufficient to cut deeply into solid masonry piers, and that only in 1907 the effect of a collision against the souther breakwater of the Admiralty Harbour, Dover, was to sever the roundhead entirely from the body of the pier, in addition to causing other serious injuries.

1921, L.G. Mouchel & Partners, Mouchel-Hennebique Ferro-concrete

The breakwater, and in particular the roundhead, has been the responsibility of Jersey Harbours for many years but day to day maintenance and isolated repairs were becoming more frequent, punctuated by emergency repair works to the face of the roundhead at the extreme end of the breakwater.

2009, Michael Grantham, Carmelo Majorana, Valentina Salomoni, Concrete Solutions, page 123