Anything done, or said; an act or action; an actual occurrence; a circumstance; whatever comes to pass; an event. (Dictionary of Law, W.C. Anderson, Chicago, 1889.)
By Lord Steyn in Jindal Iron and Steel Co Ltd & Ors v. Islamic Solidarity Shipping Company Jordan Inc (The Jordan II)  UKHL 49 at para 6:
The acronym F.I.O.S.T. stands for Free In and Out Stowed and Trimmed. There was, therefore, under the charterparty an agreement that the "Shippers/Charterers/Receivers" were to put the cargo on board, stow it, lash it, secure it, dunnage it and discharge it free of expense to the vessel. It was plainly an agreement designed to transfer responsibility for these particular functions from the shipowners to shippers, charterers and consignees. The cargo owners no longer contest the decisions at first instance and in the Court of Appeal to this effect.
Flaux J in Societe De Distribution De Toutes Merchandises En Cote D’Ivoire (t/a "SDTM-CI") & Ors v Continental Lines N.V. & Anor  EWHC 1747 (Comm) at para 20:
Clause 5 of the present charterparty [Synacomex 90] does not contain an express provision such as in clause 8 of the NYPE Form that the charterers are to load, stow and discharge the cargo. Whilst clause 4 of the charterparty does make it clear that the freight rate is on an FIOST (that is "Free In and Out Stowed and Trimmed") basis and there is some suggestion, in  of Lord Steyn’s opinion in The Jordan II, that those words amount to an agreement that the charterers are to perform the various operations, the charterparty in that case contained at clause 17 an express provision that the charterers were to put the cargo on board, trim and discharge it. The better view is that FIOST terms do not, without more, transfer responsibility for performance of the operations, as opposed to payment for them, to the charterers.