### - o -

- o : ResolverObject
- obj_len : SaveLoadParams
- object_height : BuildObjectWindow
- OBJECT_MARGIN : BuildObjectWindow
- occupied : RoadStop::Entry
- offs : TileHighlightData
- offset : BmpInfo , CompanyManagerFaceBitsInfo , LoggedChange , NIProperty , NICallback , UnmappedChoiceList , Blitter_8bppOptimized::SpriteData , OldChunks
- offsets : LanguagePackHeader
- oil_refinery : ExtraPaletteValues
- oil_refinery_limit : GameCreationSettings
- ok_btn : OskWindow
- okay : PBSTileInfo
- old : Vehicle
- old_d : UnmappedChoiceList
- old_economy : CompanyProperties
- old_max_loan_unround : Economy
- old_max_loan_unround_fract : Economy
- old_new_hash : Vehicle
- old_refittable : ShipVehicleInfo
- old_tile : GetNewVehiclePosResult
- oldval : LoggedChange
- online : NetworkGameList
- openlist_hash : AyStar
- openlist_queue : AyStar
- openttd_id : LanguageMap::Mapping
- opf : PathfinderSettings
- order : GameSettings , Listing , RefitWindow
- order_over : OrdersWindow
- order_review_system : GUISettings
- orderindex : OrderBackup
- orders : OrderBackup , Vehicle
- ordinal_width : CompanyLeagueWindow
- orientation : RailStationGUISettings
- orig_list : NewGRFWindow
- orig_str_buf : OskWindow
- original_image_index : Engine
- original_md5sum : GRFConfig
- os2_bmp : BmpInfo
- other_accepted : CargoesField
- other_company_name : CompanyNewsInformation
- other_produced : CargoesField
- outersize : TileHighlightData
- outgoing_queue : ServerNetworkGameSocketHandler
- overdrawn_ops : Squirrel
- override : GRFFileProps
- overtaking : RoadVehicle
- overtaking_ctr : RoadVehicle
- own_name : LanguagePackHeader
- owner : BaseStation , Window , Group , TileDesc , Industry , CargoPayment , Vehicle
- owner_type : TileDesc