1) The pike was a stack of hay made up of several hay-cocks, with a pointed top.
1563 one pike of haye att langmouthe, Leake
1642 if there bee any hey to spare ... wee either stacke it abroade or else make it up in a pyke ... therewith intending to fother our sheepe in winter, Elmswell. The verb is also on record: 1787 Aug. 1 Men mowing Barley Garth ... Got half into pike. Aug. 4 Our people piked rest of the Ings, Sessay.
2) A pitchfork.
1642 theire flayle-handstaffes they ... putte them into an oven ... and lette them lye there a whole night, and this will dry up the moisture and make them lighter ... and keepe them from casting [warping].This is the course they take with their pikes, Elmswell.
3) No definition available
Said to mean ‘pointed’ in the place-names Pike Law and Pike Low, both recorded by Smith three times and both having hl?w as the suffix. The ‘law’ could refer to a hill or burial mound but in Yorkshire it was also used of boundary cairns in the Middle English period. Since so few of the Pennine hills are pointed it prompts me to suggest that ‘piked law’ meant a hill which had a pointed heap of stones rather than a pointed hill. In a description of the bounds of Gisburn Forest in 1205-11 the line ran usque ad Pykcros super Manebent. A map of common lands in Ingleborough, dated 1619, places The Pyke aboue Hamerton folde on the hill called Moughton which is undoubtedly rocky but not pointed, often described as a limestone plateau. The pointed symbol on the map almost certainly identifies a prominent boundary cairn. Some of the earliest examples of the compound Pike Law are in charters relating to the lands held by Kirkstall Abbey, notably those for the period 1329-33 which define the boundaries between Blackburnshire and Barnoldswick, for example de Oxgille vsque Pikedlawe que vocatur Aleynsete. This was hilly country, even if the hills were not ‘pointed’, but the same cannot be said for the low-lying land between Alwoodley and Chapel Allerton near Leeds which is mentioned in an undated charter: vnam acram terre in campo de Alretun, iuxta Pikedlawe. The two names are part of a substantial corpus of similar names which includes several Pike Hills and Pikedaws: the latter has the suffix haugr which is the Old Norse equivalent of hl?w and it was also commonly used as a boundary marker.